Ensure validation messages are shown within the milestone form

Fixes a bug where upon entering data to create an invalid milestone via the Web UI or the API would raise an exception rather than render the validation messages

We'd rather render the validation messages to inform the user than raise an exception and result in a 422 error being displayed

Closes #22033

See merge request !6345

Reset pushes_since_gc counter before specs run to ensure starting point is 0

See merge request !6406

Render invalid template for open merge requests without source project

If source project was removed and merge request for some reason wasn't closed is rendered `invalid` template. Fix !6177

Fix #22248 

See merge request !6383

Add missing spec for ProtectedBranches::CreateService

While working on !6399, I noticed there was no spec for this class so I added one.

See merge request !6405

* Remove call to Milestone#save! instead just Milestone#save
* Add safety specs to stop a regression

Fixes #22033

Refactor boards_spec.rb to avoid code duplication

Originally created to address #21197, but !6224 solved the intermittent spec failures.

See merge request !6197

Return created status

## What does this MR do?
Properly handles status created which results in 500 when viewing Merge Request pipelines.

## 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?

- Tests
  - [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 you do - 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 #22286

See merge request !6404

Document how to download the latest build artifacts

## What does this MR do?

Document how to download the latest build artifacts.

Closes gitlab-org/gitlab-ce#22273

See merge request !6401

[ci skip]

Update GitHub importer documentation  to reflect current importer state

## What does this MR do?

Update the Github importer documentation to reflect the current importer state.

## What are the relevant issue numbers?

https://gitlab.com/gitlab-org/gitlab-ee/issues/904

## Does this MR meet the acceptance criteria?

- [X] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)


See merge request !5987

improve wording on build and push images using GitLab CI docs

## What does this MR do?

Improve wording on build and push images using GitLab CI docs

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

No

## Why was this MR needed?

Poor wording

## Does this MR meet the acceptance criteria?

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

See merge request !6001

Formatting fix in doc/ci/examples/README.md

Just a tiny fix of wrongly formatted markdown link.

See merge request !6398

docs: fix typo, it should refer to `domain_blacklist_enabled` setting

## What does this MR do?

fix the documentation

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

N/A

## Why was this MR needed?

typo fix

## What are the relevant issue numbers?

N/A

## Screenshots (if relevant)

N/A

## Does this MR meet the acceptance criteria?

yes, it's just a typo fix in the documentation without any code or business logic changes

See merge request !5899

Document IAM Profile AWS S3 configuration key.

## What does this MR do?
Document additional parameters available to the backup rake job configuration. 

## Are there points in the code the reviewer needs to double check?
Probably not.

## Why was this MR needed?
Un-documented configuration options

## What are the relevant issue numbers?
#12756

## Does this MR meet the acceptance criteria?

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

See merge request !5910

Originally created to address #21197, but !6224 solved the intermittent spec
failures.

Fix line diff side-by-side line highlighting

## What does this MR do?

Fixes line highlighting in diff side-by-side view from working correctly.

The JS was looking for a class, but the class doesn't exist & instead it was a data attribute.

## Screenshots (if relevant)

![Screen_Shot_2016-09-13_at_10.26.15](/uploads/7aca730efb14d7bd6bad2a8712fe39d2/Screen_Shot_2016-09-13_at_10.26.15.png)

See merge request !6316

Scrolls active tab into middle of nav on mobile

## What does this MR do?

On mobile (or smaller screens) it scrolls the currently active tab into the middle of the nav.

## Screenshots (if relevant)

![Screen_Shot_2016-09-15_at_09.38.55](/uploads/4170271b53b9509a385fa7844fb3dc78/Screen_Shot_2016-09-15_at_09.38.55.png)

See merge request !6363

Simplified the CSS for issue boards

## What does this MR do?

It gained a lot of extra cruft through the different improvements etc. This removes a lot of the stuff which would hopefully also speed up the browser rendering.

- Removed flexbox from a lot of things which in turn reduces it's complexity.
- Removed styles that either aren't used or aren't needed.
- Various other improvements to the CSS.

Basically just improved the CSS by removing overly complex CSS. There are no visible changes to issue boards, just less CSS for the same results.

See merge request !6352

Fixed commit search UI

## What does this MR do?

Fixes the UI for commits in search.

If the scope of the search is commits then it renders the list in a `ul` to match the same styling as that on the commits UI.

## Screenshots (if relevant)

![Screen_Shot_2016-09-05_at_15.30.12](/uploads/f567a224be44d5a9b015ac5d1c399bd7/Screen_Shot_2016-09-05_at_15.30.12.png)

## What are the relevant issue numbers?

Closes #21868

See merge request !6205

Fix anchor icon regression

An error in scss prevented the markdown header `:hover` anchor icon svg from linking correctly:

![Screen_Shot_2016-09-14_at_4.06.19_PM](/uploads/f4d31a17a58bd7cbde572f91c316dfe1/Screen_Shot_2016-09-14_at_4.06.19_PM.png)

The following currently 404s:  
<https://gitlab.com/assets/icon_anchor.svg>  

## What are the relevant issue numbers?

#20459 & !5577

See merge request !6358

Replace contributions calendar timezone payload with dates

## What does this MR do?
Fixes a ~regression bug introduced in !5784 whereby the calendar squares would not render due to a timezone mismatch between the server timezone and the browser (user) timezone. I am now returning the dates instead of the timezone from the backend. There's a good chance we will still have a calendar off by one error (which is an existing issue #1943) but passing dates should make sure that the calendar activity squares render correctly across timezones.

## Are there points in the code the reviewer needs to double check?
Double check that this displays the correct calendar squares when the GitLab instance is hosted in a different timezone than the user viewing it

## Why was this MR needed?
Fixes ~regression issue 😞 

## Screenshots (if relevant)
Before:
![Screen_Shot_2016-09-13_at_9.47.06_PM](/uploads/d8b41b9b43320f021452e39f29b0e194/Screen_Shot_2016-09-13_at_9.47.06_PM.png)

After:
![Screen_Shot_2016-09-13_at_9.46.11_PM](/uploads/e09a3b35eef77ee1cf73b924c3815d3a/Screen_Shot_2016-09-13_at_9.46.11_PM.png)

## 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 you do - 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 #21921

See merge request !6336

Use oj gem for faster JSON processing

See merge request !6395

It's mainly intended to improve Elasticsearch indexing performance
(through multi_json gem), but other gems could benefit from it too, like
grape.

Bump fog-aws and other dependent modules

fog-aws CHANGELOG: https://github.com/fog/fog-aws/blob/master/CHANGELOG.md

Notable improvements:

* Support for ap-south-1 region
* Fix for empty ETag values

Closes #22260

See merge request !6392

Merge branch '22256-nomethoderror-api-entities-note-missing-attribute-note-on-awardemoji-0x00000015142480' into 'master'

Fix API notes endpoint when posting only emoji

Closes #22256

See merge request !6387

Closes #22260

MergeRequest#environments now returns an empty array when diff_head_commit is nil

## Does this MR meet the acceptance criteria?

- [x] No CHANGELOG needed for a bug introduced in an RC.
- Tests
  - [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)
- [ ] 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)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?

Closes #22246

See merge request !6379

Fixes incorrect reference to `@repository.root_ref` in _readme.html.haml.

Fixes #22083

See merge request !6369