Fix save button on pipelines settings page

## What does this MR do?

This MR fixes 'Save button' on pipeline settings page, which didn't change state to enabled after saving settings.

## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- Tests
  - [x] Added for this feature/bug
  - [ ] All builds are passing

## What are the relevant issue numbers?

Closes #23431

See merge request !6955

Make cancelled pipelines being able to retry

## What does this MR do?

Make cancelled pipelines being able to retry

## Does this MR meet the acceptance criteria?

- [x] [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
  - [x] Added for this feature/bug

## What are the relevant issue numbers?

Closes #23326

See merge request !6927

Add visibility level to project repository

implements #19734

See merge request !6396

Add a be_like_time matcher and use it in specs

## What does this MR do?

Introduces a be_like_time matcher and refactors existing code to use it

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

A few sites use be_within(2.seconds) or 5.minutes - I didn't change those

## Why was this MR needed?

A custom matcher helps to document that we need to compare times loosely, and keeps the fudge factor from being declared in multiple places.

## Screenshots (if relevant)

## 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 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 !6935

See merge request !6936

Fix the diff in the merge request view when converting a symlink to a regular file

## What does this MR do?

It fixes a bug described in #21610

## Why was this MR needed?

There was a regression introduced in https://gitlab.com/gitlab-org/gitlab-ce/commit/cd7c2cb6ddd4d9c9f9bdae00c887c0022c121c17

## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry 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?

Fixes #21610

See merge request !6828

Execute specific named route method from toggle_award_url helper method

See merge request !6848

Avoid race condition when expiring artifacts

## What does this MR do?

It may happen that job which purpose is to remove expired artifacts will be executed asynchronously when, in the meantime, project associated with given build gets removed by another async job. In that case we should not remove artifacts because such build will be eventually removed anyway along with artifacts, when project removal is complete.

## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- Tests
  - [x] Added for this feature/bug
  - [x] All builds are passing

## What are the relevant issue numbers?

Closes #22296

See merge request !6881

* upstream/master: (58 commits)
  Update endpoint to username validator
  change border color to variable
  Add todo for deprecated user routes and more information about deprecation to changelog
  Provide better error message to the user
  Apply better hierarchy to markdown headers and issue/mr titles
  Swapped button text manipulation outcomes for the toggle query
  Fixed find file keyboard navigation
  Update CHANGELOG for 8.12.7
  Added download-button class and applied button margin
  Enable activerecord_sane_schema_dumper for test
  Updated logo from @luke
  Fix broken specs on MySQL after https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/6896
  Fix Test Env (proper error handling when gitlab-shell is not clonned)
  Fix randomly crashing spinach test for merge request
  [Great spinach fix] Replace gsub with delete
  Remove carriage returns from commit description as summary is on a newline and will always include carriage returns
  Convert due_date_select.js filetype to es6.
  Stop directly parsing due_date with Date.parse, prefer parsing implicitly.
  Improve spec for pipeline metrics worker
  Add Pipeline metrics worker
  ...

[ci skip]

Resolve Merge conflicts in editor

## What does this MR do?

This is the second iteration of https://gitlab.com/gitlab-org/gitlab-ce/issues/20344 which now allows to resolve conflicts manually providing an editor to the user.

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

- Previous implementation has been refactored almost from the ground up.
- Also some components like `parallel-conflict-lines` has been optimized to work well with PhantomJS.
- The app and files required files are loaded only when needed. `merge_conflicts_bundle.js` is only loaded in `/<group>/<project>/merge_requests/<Id>/conflicts` only

## Why was this MR needed?

Some MRs were unable to be solved interactively in the UI, with this MR we let the user to manually fix complex merge request conflicts.

## Screenshots (if relevant)

<img src="/uploads/33a016f025bd590b1fc6eeee1ee11626/Screen_Shot_2016-09-19_at_1.39.39_PM.png" width="800">

## Does this MR meet the acceptance criteria?

- [x] [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
  - [x] 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)
- [ ] 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 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 https://gitlab.com/gitlab-org/gitlab-ce/issues/20344, https://gitlab.com/gitlab-org/gitlab-ce/issues/3567.

See merge request !6374

Fixes endpoint to username validator

Fixes failing specs on master. Introduced here https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/6328

See merge request !6951

Merge branch '22191-delete-dynamic-envs-mr' of gitlab.com:gitlab-org/gitlab-ce into 22191-delete-dynamic-envs-mr

Apply better hierarchy to markdown headers and issue/mr titles

## What does this MR do?
Applies better hierarchy to markdown headers and issue/mr titles

## Why was this MR needed?
Titles of issues/mr's were smaller than h1, leading to strange hierarchy when reading descriptions

## Screenshots (if relevant)

### Before:
![Screen_Shot_2016-10-14_at_1.31.37_PM](/uploads/79b6b16b8ed1b3b49578161eea1f0e42/Screen_Shot_2016-10-14_at_1.31.37_PM.png)

### After:
![Screen_Shot_2016-10-14_at_1.31.26_PM](/uploads/f710b63c112e342c5429810984079da6/Screen_Shot_2016-10-14_at_1.31.26_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 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 #21395

See merge request !6904

Fix toggling of expand/hide pipeline graph button

## What does this MR do?

Corrects the toggling behaviour given that the pipeline graph now starts in a different state.

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

## Why was this MR needed?

Expand/hide toggling UI is buggyyy

## Screenshots (if relevant)

![2016-10-14_18.15.41](/uploads/7cdeef02c0b8aa4266f2878866e4b633/2016-10-14_18.15.41.gif)

## 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 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 #23358

See merge request !6898

Rename users routing from /u/:username to /users/:username for
consistency with other routes

Renames /u/:username to /users/:username

To follow consistency with other routes (like groups) and
UsersController name.
Now when you can use `/:username` for accessing user page there is no
need in shortcut like `/u/`

See merge request !6851

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

It may happen that job meant to remove expired artifacts will be
executed asynchronously when, in the meantime, project associated with
given build gets removed by another asynchronous job. In that case we
should not remove artifacts because such build will be removed anyway,
when project removal is complete.