Do not use MergeRequest#commits in define_pipelines_vars

## What does this MR do?

`MergeRequest#commits` requires merge_request_diff to be present.
This is not the case when creating a new merge request.

## What are the relevant issue numbers?

Fix up for https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/7568

Fixes https://gitlab.com/gitlab-org/gitlab-ce/issues/24798

See merge request !7664

Preserve optional second parameter in NewNoteWorker jobs
    
Closes #24678

See merge request !7602

Handle orphans when removing soft deleted groups

This fixes the migration from https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/7528 so it handles orphans as mentioned in https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/7528/diffs#note_18800962.

This needs to go in 8.14.0 as otherwise customers may run into the same problem.

See merge request !7657

Add new image for Cycle Analytics

See merge request !7666

Docs on Mattermost commands

Still needs some screenshots, depends on: https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/7558

/cc @ayufan @SeanPackham

See merge request !7567

Add help section for MM commands

## What should this MR do

Check @pedroms' design for the Mattermost service screen: https://gitlab.com/gitlab-org/gitlab-ce/issues/22540

Now this has to be implemented, I've created a clean canvas for you, @lbennett, to draw on.

## Does this MR meet the acceptance criteria?

- [x] [Changelog entry](https://docs.gitlab.com/ce/development/changelog.html) added
- Tests
  - [x] Added for this feature/bug
  - [x] All builds are passing
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if it does - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

See merge request !7558

Revert "Merge branch 'docs/jira-old' into 'master'"

See merge request !7531

Improve readability of environments table

## What does this MR do?
Fix the environments table columns width

## Before
![Screen_Shot_2016-11-21_at_18.13.00](/uploads/1771b0546eb3cb15f4894b719fd44286/Screen_Shot_2016-11-21_at_18.13.00.png)

## After
![Screen_Shot_2016-11-21_at_18.11.18](/uploads/a20194a055b6ec0f7989f0c1499883d3/Screen_Shot_2016-11-21_at_18.11.18.png)
## Does this MR meet the acceptance criteria?

- [ ] [Changelog entry](https://docs.gitlab.com/ce/development/changelog.html) added
- [ ] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [ ] API support added
- Tests
  - [ ] Added for this feature/bug
  - [x] All builds are passing
- [x] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if it does - rebase it please)
- [ ] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?

See merge request !7628

Fix undefined error in CI linter

## What does this MR do?

This MR fixes undefined error in CI linter.

## Does this MR meet the acceptance criteria?

- [x] [Changelog entry](https://docs.gitlab.com/ce/development/changelog.html) added
- [x] Tests added for this feature/bug
  
## What are the relevant issue numbers?

Closes #24759

See merge request !7650

Backport SmartInterval, PrettyTime, SubbableResource from EE.

## What does this MR do?

Backports infrastructure used for EE-only Timetracking so it can be used and improved upon in CE. 

This doesn't really need review... it was already reviewed and merged in EE. 

There are no side effects or conflicts, just three new classes added:

1. `SubbableResource` -- pubsub for ajax resources
2. `SmartInterval`-- for configurable polling
3. `PrettyTime` -- time parsing and formatting utility methods

- [x] Added for this feature/bug
- [x] All builds are passing
- [x] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if it does - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?

https://gitlab.com/gitlab-org/gitlab-ee/issues/985

https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/870

cc: @jschatz1

See merge request !7573

Restricted visibility buttons to checkboxes

## What does this MR do?

Changes the `Restricted visibility levels` settings to use checkboxes instead of a button group.

## Are there points in the code the reviewer needs to double check?

## Why was this MR needed?

## Screenshots (if relevant)

![Screen_Shot_2016-11-14_at_19.25.48](/uploads/0c6ee415ee0c89c0a7e3ffd98f88df71/Screen_Shot_2016-11-14_at_19.25.48.png)

## Does this MR meet the acceptance criteria?

- [x] [Changelog entry](https://docs.gitlab.com/ce/development/changelog.html) added
- [ ] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [ ] API support added
- Tests
  - [ ] Added for this feature/bug
  - [x] All builds are passing
- [x] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if it does - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?


Closes #18136

See merge request !7463

Issues empty state

## What does this MR do?

Adds the empty state for the project, dashboard and group issues.

## Are there points in the code the reviewer needs to double check?

## Why was this MR needed?

## Screenshots (if relevant)

### Filtered to show no issues (on group issues page in this case but also dashboard and projects)

![Screen_Shot_2016-11-08_at_20.55.56](/uploads/b598af4a8a5e2c9fbb859abf36e70e4b/Screen_Shot_2016-11-08_at_20.55.56.png)

### Project with no issues

![Screen_Shot_2016-11-08_at_20.57.08](/uploads/8f54fdf1b3101c46299249fa2944207d/Screen_Shot_2016-11-08_at_20.57.08.png)

![Screen_Shot_2016-11-08_at_20.57.17](/uploads/1d2d162e1d845dd05e945d8ebb1d2101/Screen_Shot_2016-11-08_at_20.57.17.png)

### Group with no projects with any issues

![Screen_Shot_2016-11-08_at_20.54.55](/uploads/f28dc2038839d5bda0eb37f37927d5db/Screen_Shot_2016-11-08_at_20.54.55.png)

## Does this MR meet the acceptance criteria?

- [ ] [Changelog entry](https://docs.gitlab.com/ce/development/changelog.html) added
- [ ] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [ ] API support added
- Tests
  - [ ] Added for this feature/bug
  - [ ] All builds are passing
- [ ] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [ ] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [ ] Branch has no merge conflicts with `master` (if it does - rebase it please)
- [ ] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?


Closes #20840 

Closes #20850

See merge request !7309

Make milestone page responsive

Credit to @yury-n for this one. ⭐ 🌟 ⭐  Original MR: !5255

## What does this MR do?

> Makes the milestone page more mobile friendly

## Are there points in the code the reviewer needs to double check?

> Shouldn't be but maybe double check that the views I changed are exclusively used by the milestone details page I was amending and not any other pages that I haven't tested after my changes.

Looks good to me. :) Would be awesome to have @annabeldunstone check up on the stylesheet updates.

## Why was this MR needed?

> Buttons were misaligned

> Progress bar was not 100% width

> Stats were cut in the middle

> Milestone name/date text overflow

![Screen_Shot_2016-07-14_at_5.37.49_PM](/uploads/4da67c9f81d71873188e4a5cafed8113/Screen_Shot_2016-07-14_at_5.37.49_PM.png)

![Screen_Shot_2016-07-14_at_5.41.58_PM](/uploads/b3d767ce49e37b251c3192ed051400b8/Screen_Shot_2016-07-14_at_5.41.58_PM.png)

![Screen_Shot_2016-07-14_at_5.46.41_PM](/uploads/353ad59a88f3dea9e3f88e6ea05c1af3/Screen_Shot_2016-07-14_at_5.46.41_PM.png)

## Screenshots (if relevant)

![Screen_Shot_2016-07-14_at_6.15.58_PM](/uploads/a26768701ea6cb00ccd85a5ac0772e36/Screen_Shot_2016-07-14_at_6.15.58_PM.png)

![Screen_Shot_2016-07-14_at_5.57.04_PM](/uploads/b94cf1b7593589948216342b48a19831/Screen_Shot_2016-07-14_at_5.57.04_PM.png)

## Does this MR meet the acceptance criteria?

- [ ] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- [ ] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [ ] API support added
- Tests
  - [ ] Added for this feature/bug
  - [ ] All builds are passing
- [ ] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [ ] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [ ] Branch has no merge conflicts with `master` (if you do - rebase it please)
- [ ] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?

Closes #18852

See merge request !6655

Cycle analytics second iteration frontend

## Are there points in the code the reviewer needs to double check?
Mostly typos and code guidelines.

## Why was this MR needed?
This implements the frontend part of !6859 for #23449

## Screenshots

**Initial view**
![Screen_Shot_2016-11-21_at_5.28.43_PM](/uploads/ff9cfa9c9d6c2da28c24e03e384f89af/Screen_Shot_2016-11-21_at_5.28.43_PM.png)

**Cycle Analytics with data**
![Screen_Shot_2016-11-21_at_2.09.24_PM](/uploads/18d9786c090bdd554cf786c879543302/Screen_Shot_2016-11-21_at_2.09.24_PM.png)

**User doesn't have access for a stage**
![Screen_Shot_2016-11-21_at_2.11.01_PM](/uploads/d1ea76a63f2de2224954b5f40038c488/Screen_Shot_2016-11-21_at_2.11.01_PM.png)

## Does this MR meet the acceptance criteria?

- [x] [Changelog entry](https://docs.gitlab.com/ce/development/changelog.html) added
- [ ] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [ ] API support added
- Tests
  - [ ] Added for this feature/bug
  - [ ] All builds are passing
- [ ] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [ ] Branch has no merge conflicts with `master` (if it does - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?
Closes #23449

See merge request !7366

Improve deploy message

## What does this MR do?
Improves deploy message to make it more descriptive and useable then what is already offered by deploy command.

## Does this MR meet the acceptance criteria?

- [ ] [Changelog entry](https://docs.gitlab.com/ce/development/changelog.html) added
- [ ] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [ ] API support added
- Tests
  - [ ] Added for this feature/bug
  - [ ] All builds are passing
- [ ] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [ ] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [ ] Branch has no merge conflicts with `master` (if it does - rebase it please)
- [ ] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?

See merge request !7629

Resolve "Activity entries are not loaded fully to cover full window's height"

## What does this MR do?

Fixes a bug in which a browser window large enough to encompass the default number of items in an auto-loading endless-scroll list could not trigger the loading of additional items.

## Are there points in the code the reviewer needs to double check?

I refactored activities.js and pager.js into es6 syntax while I was investigating the issue.  No changes were made other than some es6 flourishes and eslint conformity, so nothing should be effected, but perhaps best to double check other pages which utilize these scripts.

## Screenshots (if relevant)

![endless-scroll-fixed](/uploads/b672b606826af745528c209ab6cfe95c/endless-scroll-fixed.gif)

## Does this MR meet the acceptance criteria?

- [x] [Changelog entry](https://docs.gitlab.com/ce/development/changelog.html) added
- Tests
  - [x] All builds are passing
- [x] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if it does - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?


Closes #24499

See merge request !7608

explicitly disable eslint inline

## What does this MR do?

Explicitly disables eslint inline.

I.E. `/* eslint-disable */` => `/* eslint-disable max-len, no-new, ... */`

I used the script from https://gitlab.com/lbennett/eslint-dsblr.

## Are there points in the code the reviewer needs to double check?

## Why was this MR needed?

It will help refactor out eslint issues for older files.

## Screenshots (if relevant)

## Does this MR meet the acceptance criteria?

- [ ] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG.md) entry added
- [ ] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [ ] API support added
- Tests
  - [ ] Added for this feature/bug
  - [x] All builds are passing
- [x] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if it does - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?

See merge request !7229

Fix errors happening when source branch of merge request is removed and then restored

See merge request !7568

Remove v-html

## What does this MR do?
Uses string interpolation instead of `v-html` to prevent xss attacks.

## Does this MR meet the acceptance criteria?

- [ ] [Changelog entry](https://docs.gitlab.com/ce/development/changelog.html) added
- [ ] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [ ] API support added
- Tests
  - [ ] Added for this feature/bug
  - [ ] All builds are passing
- [x] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if it does - rebase it please)
- [ ] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?

See merge request !7616

Adds a flag to reflect whether or not there is data in cycle analytics

See merge request !7622

Fix permissions error

## What does this MR do?
Gives the permissions to the child row in order to render it properly.

## Does this MR meet the acceptance criteria?

- [ ] [Changelog entry](https://docs.gitlab.com/ce/development/changelog.html) added
- [ ] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [ ] API support added
- Tests
  - [ ] Added for this feature/bug
  - [ ] All builds are passing
- [ ] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [ ] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [ ] Branch has no merge conflicts with `master` (if it does - rebase it please)
- [ ] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?

See merge request !7627

Send registry address with build payload

## What does this MR do?

Adds `registry_url` as a part of a build payload, when sending a response to a GitLab Runner which requested a new build.

## Are there points in the code the reviewer needs to double check?

Change in `lib/ci/api/entities.rb`.

## Why was this MR needed?

This is one of the steps needed to add support for private/protected registries hosted with GitLab CE/EE.

## Screenshots (if relevant)

## Does this MR meet the acceptance criteria?

- [x] [Changelog entry](https://docs.gitlab.com/ce/development/changelog.html) added
- [ ] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [x] API support added
- Tests
  - [x] Added for this feature/bug
  - [ ] All builds are passing
- [ ] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [ ] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [ ] Branch has no merge conflicts with `master` (if it does - rebase it please)
- [ ] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?

Related to gitlab-org/gitlab-ci-multi-runner#1828, gitlab-org/gitlab-ci-multi-runner!386, gitlab-org/gitlab-ci-multi-runner#1434

See merge request !7474

Add deploy chat command

This adds a new ChatOps command:
```
/trigger deploy <environment> to <environment>
```

See merge request !7619

Fix 500 error when group name ends with git

Closes https://gitlab.com/gitlab-com/support-forum/issues/1298
Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/24742

See merge request !7630

Allow JIRA references for project snippets

closes #24303

See merge request !7541

Allow to block JIRA events for commits and merge requests

implements #5541 

See merge request !7469

Add JIRA remotelinks and prevent duplicated closing messages

implements #13232  
closes #20479   

See merge request !7413

makes compare previous version link easily clickable

## What does this MR do?
This MR does a minor fix about `Compare previous link` which is not easily clickable when long commit list are expanded

## Are there points in the code the reviewer needs to double check?
NR
## Why was this MR needed?
For better UX and make browse easy

## Screenshots (if relevant)

**Before:**
![BrRs](/uploads/11e60ef150a9035ae94d6ed69c3038b5/BrRs.gif)

**After**
![2016-11-19_02.02.42](/uploads/961bac1ddcdc4338ac72bc690c52b7f1/2016-11-19_02.02.42.gif)

## Does this MR meet the acceptance criteria?

- [ ] [Changelog entry](https://docs.gitlab.com/ce/development/changelog.html) added
- [ ] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [ ] API support added
- Tests
  - [ ] Added for this feature/bug
  - [x] All builds are passing
- [ ] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if it does - rebase it please)
- [ ] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?


Closes #24658

See merge request !7587

Smarter cache invalidation

Fixes https://gitlab.com/gitlab-org/gitlab-ce/issues/23550

See merge request !7360

Do not create TODO when build is allowed to fail

## What does this MR do?

Do not create a TODO when build that failed is allowed to fail.

## Does this MR meet the acceptance criteria?

- [x] [Changelog entry](https://docs.gitlab.com/ce/development/changelog.html) added
- [x] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- Tests
  - [x] Added for this feature/bug
  - [ ] All builds are passing

## What are the relevant issue numbers?

Closes #22280

See merge request !7618

Add constraints to group id in routing

To prevent 404 when visit page like https://gitlab.com/groups/group.with.dot/activity

Fixes https://gitlab.com/gitlab-org/gitlab-ce/issues/24622

See merge request !7614

Added permissions per stage to cycle analytics endpoint

See merge request !7613

Backport some changes done from Time Tracking feature in EE.

See merge request !7604

Fixes regression causing an error message to appear when user first enters the Merge Request form.

Closes #24627

See merge request !7599

Merge branch '24616-mr-shows-the-build-for-this-merge-request-failed-although-builds-still-running' into 'master'

Resolve "MR shows "The build for this merge request failed" although builds still running"

Closes #24616

See merge request !7579

Merge branch '24552-js-environment-timeago-is-not-rendered-and-text-shows-object-object-in-mr-widget' into 'master'

Fix timeago rendering for environment timeago

## What does this MR do?

## Are there points in the code the reviewer needs to double check?

## Why was this MR needed?

## Screenshots (if relevant)

## Does this MR meet the acceptance criteria?

- [ ] [Changelog entry](https://docs.gitlab.com/ce/development/changelog.html) added
- [ ] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [ ] API support added
- Tests
  - [ ] Added for this feature/bug
  - [ ] All builds are passing
- [ ] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [ ] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [ ] Branch has no merge conflicts with `master` (if it does - rebase it please)
- [ ] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?


Closes #24552

See merge request !7539

Add API endpoint for creating a pipeline

Fixes #23468

See merge request !7209

Resolve "Display "folders" for environments"

## What does this MR do?
Adds the ability to show the grouped environments inside "folders".
Adds several reusable vue components in order to accomplish the recursive tree data structure presented.

For the individual components, Jasmine tests were added.
For the ones that depend of an API response, rspec tests are used.


## Screenshots (if relevant)
![Screen_Shot_2016-11-16_at_02.00.13](/uploads/1278012c8639b999b53f080728d283e1/Screen_Shot_2016-11-16_at_02.00.13.png)
![Screen_Shot_2016-11-16_at_02.00.25](/uploads/a3d65416ddb553e1b8f0f4c8897a75dc/Screen_Shot_2016-11-16_at_02.00.25.png)
![Screen_Shot_2016-10-17_at_16.08.50](/uploads/af63efe1d2cbd5fc069408622ef4b607/Screen_Shot_2016-10-17_at_16.08.50.png)


![environments](/uploads/b5a1801766d82ab176fc60f96b6968cb/environments.gif)
## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG.md) entry added
- [ ] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [ ] API support added
- Tests
  - [x] Added for this feature/bug
  - [ ] All builds are passing
- [x] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if it does - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?
Closes #22539

See merge request !7015