Allow certain Sidekiq jobs to be throttled

## What does this MR do?

Allows certain slow running Sidekiq jobs to be throttled. It is disabled by default and can be enabled via the Application Settings. 

![Screen_Shot_2016-11-04_at_4.51.24_PM](/uploads/a1f1d24c693fcdb278602765cd404d94/Screen_Shot_2016-11-04_at_4.51.24_PM.png)

## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG.md) entry 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
  - [x] All builds are passing

## What are the relevant issue numbers?

Related to #23352

See merge request !7292

Migration to Vuejs version 2

List of required changes for our Vue usages 

- `init` ➡ `beforeCreate`
- `read` ➡ `mounted`
- `$els` ➡ `$refs`
- 🚫 `$remove` completely removed. ✅ Use `indexOf` and `splice`
- 🚫 HTML embedding with `{{{ }}}` is deprecated. ✅ Use `v-html`


See merge request !7254

UX guide restructure

The goal of this MR was to update the current UI guide to more of an UX guide (starting to detail when to use certain controls and patterns), and add structure to help organize the information. This initial version of the UX guide also lays down the groundwork for principles and personality. This guide is currently documenting the existing design, and will continue to be updated as the design evolves.

Some inspiration/references used:
- https://medium.com/ge-design/ges-predix-design-system-8236d47b0891#.nkf0chj8r
- http://uxcellence.com/2015/11/04/product-principles/
- https://blog.asana.com/2013/10/design-principles/

See merge request !7142

[ci skip]

19205 Redesign group page header to match new navigation

## What does this MR do?
Redesigns group page to match comps

## Screenshots (if relevant)
Before:
![Screen_Shot_2016-11-08_at_12.50.53_PM](/uploads/6c958e2ab05c1a73c9a96de25490ba2b/Screen_Shot_2016-11-08_at_12.50.53_PM.png)
After:
![Screen_Shot_2016-11-08_at_12.50.34_PM](/uploads/822f81df8a0f82a4bdeee3739be5d1f7/Screen_Shot_2016-11-08_at_12.50.34_PM.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 #19205

See merge request !7363

Remove project_title additions from builds and environments

## What does this MR do?

Removed soon-to-be un-needed project title additions from builds and environments.

**This MR depends on !5998, which introduces subnav to these pages. Without it we're just removing a useful link.**

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

@iamphill Is this right of me? One of these still exists in `projects/artifacts/browse`, I'm not sure whether to fix the issue with `project_title`, which already has some issues with its chevron, or just remove it as it will soon be redundant.

## Why was this MR needed?

## Screenshots (if relevant)

**BEFORE:**

![Screen_Shot_2016-10-27_at_14.58.22](/uploads/2915289fb06603c33d1abbcdab70c962/Screen_Shot_2016-10-27_at_14.58.22.png)

**AFTER:**

![Screen_Shot_2016-10-27_at_14.58.29](/uploads/ad8574aeaa6771737bb9002d749b5559/Screen_Shot_2016-10-27_at_14.58.29.png)

## 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
  - [ ] 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 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 #21764

See merge request !6160

Account for fixed position MR when scrolling to elements

## What does this MR do?

This MR accounts for the new merge request fixed affix bar when scrolling to an element on the MR page.

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

## Why was this MR needed?

The fixed MR tabs bar was not being taken into account when shifting permalink scroll targets so that they are unobscured by navigation elements.

## Screenshots (if relevant)

Issues discussion permalink:
![Screen_Shot_2016-10-26_at_12.29.26_AM](/uploads/e278f784252f2b79c466f56b4f36d198/Screen_Shot_2016-10-26_at_12.29.26_AM.png)

Merge request discussion permalink:
![Screen_Shot_2016-10-26_at_12.28.26_AM](/uploads/1e57357fffb815b217484f09377f3c23/Screen_Shot_2016-10-26_at_12.28.26_AM.png)

Merge request diff permalink:
![Screen_Shot_2016-10-26_at_12.29.02_AM](/uploads/269f3a4a4075932355f665322387db86/Screen_Shot_2016-10-26_at_12.29.02_AM.png)

Commit diff page permalinks work as well, but aren't highlighted currently (see: #23696)

## Does this MR meet the acceptance criteria?

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

Closes #23520

See merge request !7051

Fix project records with invalid visibility_level values

See merge request !7391

Fix the collapsed diff  when converting a symlink to a regular file

#21610 
!6828

See merge request !6953

Require projects before creating milestone

Closes #24101

See merge request !7301

Use GitLab.com link, remove GitHub link

Fix dead link GitHub=>GitLab

See merge request !7418

Use config param in `Repository#update_ref!`

See merge request !7395

Block out pages needed for ux_guide

Add resources stub to ux_guide home

Fill out principles and basics

Add TOC to basics

Move all of UI guide to new UX guide structure

Add first level structure on ux-guide pages

Add more details to buttons

Add button images. Update link on development

Renamed surfaces to templates. Add tooltip details

Update typography and icons on Basics page

Add images for color. First draft of voice and tone

Delete findings page

Refine pages. Fill out Surfaces pages

Clean up layout on basics, surfaces, features. Add anchorlinks and counts to components

Fill out components page

Add item title and system info block

Fill out Features page

Switch tooltip placement image

Remove additional padding on right-aligned items in MR widget.

## What does this MR do?
Remove additional padding on right-aligned items in MR widget. So links look aligned.

## Are there points in the code the reviewer needs to double check?
No.

## Why was this MR needed?
Because the links are not aligned.

## Screenshots (if relevant)
![Screen_Shot_2016-11-10_at_22.38.26](/uploads/a1deacb77483125df3c25c320f53b579/Screen_Shot_2016-11-10_at_22.38.26.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
- [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 #24369

See merge request !7411

Removed gray button styling from todo buttons in sidebars

## What does this MR do?
Removes gray button styling from todo buttons in sidebars

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


## Why was this MR needed?
gray buttons are inconsistent and look disabled

## Screenshots (if relevant)

before:
![image](/uploads/98644ce1df8c903a2409fa066bca8195/image.png)

after:
![image](/uploads/a2eb8a9c40c4e5cc081553647bde8235/image.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
- [ ] 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 #24279

See merge request !7387

Fixes #24369.