Allow users to seed the initial runner registration token using an environment variable

## What does this MR do?
Allow users to seed the initial runner registration token using an environment variable

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

- Naming, do we want to make sure we are clear it's the 'registration' token. Like GITLAB_RUNNER_REGISTRATION_TOKEN vs what I have now, GITLAB_RUNNER_TOKEN
- Not sure we've tested a seed fixture before, I just made up a directory structure for the test

## Why was this MR needed?

At the moment I want to use this in our idea to production demo:  https://gitlab.com/gitlab-org/gitlab-ce/issues/22190

This is useful for when runner is bundled with gitlab, like in a kubernetes stack, and we want the runner to be able to register with gitlab as soon as they both come up.

## Does this MR meet the acceptance criteria?

- [x] [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
  - [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)
- [ ] 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 !6642

Fix Slack pipeline message by API

Pipelines triggered from API don't have a corresponding
user, so we show that it's from API, same as from the
web UI

Closes #25609

See merge request !8059

Introduce $CI_BUILD_REF_SLUG

## What does this MR do?

Adds `$CI_BUILD_REF_SLUG` to the variables exposed to the runner. This is based on `$CI_BUILD_REF_NAME` but lowercased, shortened to 63 bytes maximum, and with characters invalid in URLs and domain names replaced with `-`. 

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

Slugs don't have a uniqueness guarantee. !7983 introduces an environment name slug which *is* unique, so I'm not as exercised about this as I was.

Should the slug be published in the API? It's available through the `variables` endpoint, but perhaps it should be part of `GET /project/:id/builds` ?

I've called it `ref_slug` rather than just `slug` as there are number of possibilities for slugification in a build (unlike an environment, where only the name makes sense to slugify).

## Why was this MR needed?

`$CI_BUILD_REF_NAME` is not suited for URLs and domain names, given the list of valid characters in a git ref. 

## Screenshots (if relevant)

## 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)
- [ ] API support added
- 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 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 #22849

See merge request !8072

Fix transient failure on AnalyticsBuildEntity

AnalyticsBuildEntity uses `Time.now` to calculate durations, and on slow running builds could fail this spec. Mocking with `Timecop` should be sufficient to fix this.

Fixes https://gitlab.com/gitlab-org/gitlab-ce/issues/25500

See merge request !8082

Delete more page specific css

* Moves emojis and icons into `framework`
* Comments out unused bootstrap imports (we can remove them entirely later)

See merge request !7961

Explicitly declare all javascript globals and all eslint rule violations

This merge request takes every single external global variable referenced within a javascript file and explicitly marks it with a `/* global Foo */` comment block at the top of the script.

This also expands all blanket instances of `/* eslint-disable */` with an explicit list of disabled rules.  This is useful because if we need to search for violations of a particular rule we can simply grep the codebase for something like `no-unused-vars` or `semi` and find all of the places where this rule has yet to be fixed.

Lastly, it also removes and resolves any existing `no-undef` eslint violations.  This is useful for catching mistakes like forgetting to declare a variable with `var`/`let`/`const` which can cause hard to find bugs.

## What does this MR do?

1. Looks for generic uses of `/* eslint-disable */` and refactors them into individual rule exceptions.
2. Looks for all occurrences of `/* eslint-disable ... no-undef */` and resolves them by either fixing bugs or declaring globals with `/* global Foo */`.

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

This touches a lot of files, most changes touch nothing other than comment blocks or whitespace.  The exceptions are the following 14 files which required some small bug fixes after removing `no-undef`:

- api.js
- breakpoints.js
- build.js
- commits.js
- diff_notes/components/jump_to_discussion.js.es6
- gfm_auto_complete.js.es6
- gl_dropdown.js
- groups_select.js
- importer_status.js
- namespace_select.js
- notes.js
- preview_markdown.js
- projects_list.js
- single_file_diff.js

## Why was this MR needed?

Removal of ~"technical debt" and some necessary changes to help !7288 

## Screenshots (if relevant)

N/A

## 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)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?

N/A

See merge request !8043

Username exists check respects the relative root URL

## What does this MR do?

The path for checking if the username exists was hardcoded to as a absolute URL which broke in relative path installs. This fixes that by respecting the relative path.

## What are the relevant issue numbers?

Closes #25548

See merge request !8092

Removing and combining sass variables

* Removes/combines a good portion of our many shades of gray, according to https://gitlab.com/gitlab-org/gitlab-ce/uploads/207006b0aeadee57499c891f173198f4/Shades_of_grey_-_combined.png
* Renaming variables according to saturation etc will be in separate MR

See merge request !8052

Introduce deployment services, starting with a KubernetesService

## What does this MR do?

Adds a minimal `KubernetesService` and introduces the idea of deployment services, generally.

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

## Why was this MR needed?

Two issues scheduled for 8.15 both require a Kubernetes service - #22864 and #23580 - but they use it for very different things. Add a minimal kubernetes service to avoid conflicts later.

## Screenshots

![Screen_Shot_2016-12-14_at_12.44.13](/uploads/77d38baf2a196118f0cf7e2b996a65f3/Screen_Shot_2016-12-14_at_12.44.13.png)

## 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)
- [x] API support added
- 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 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 #22985

See merge request !7994

add node_modules to our eslintignore settings

## What does this MR do?

Adds `/node_modules` directory to `.eslintignore` so we don't lint npm modules in our build process.

## 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
- [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 #25690

See merge request !8089

Remove white space between nav items

Fixes annoying white space between items on navigation bars.

Before
![Screen_Shot_2016-12-13_at_6.06.11_PM](/uploads/605b49822f93168901bedc5ceb6490a3/Screen_Shot_2016-12-13_at_6.06.11_PM.png)

After
![Screen_Shot_2016-12-13_at_6.06.22_PM](/uploads/5c2e6432be477deaaf544cf81ec493e9/Screen_Shot_2016-12-13_at_6.06.22_PM.png)

See merge request !8078

Cursor now changes to a pointer when mousing over stages on Cycle Analytics page

When mousing over the different stage headers on the Cycle Analytics page, the mouse cursor will now change to a pointer, indicating these sections are clickable.

Closes #24803  

cc: @awhildy

See merge request !7921

Closes #25548

Adds tests for Custom Event polyfill

## What does this MR do?
Adds tests for CustomEvent polyfill.

## 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
  - [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?
Closes #24927

See merge request !7996

Modify namespace name and path validation

## What does this MR do?

* Allow same namespace name with different parent_id
* Allow same namespace path. Uniq validation should be handled by routes table

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

migrations

## Why was this MR needed?

So we can use same name in different nesting like: 

```
gitlab-ce/foo
gitlab-com/foo
foo/gitlab-ce
```

## Screenshots (if relevant)

no

## 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
  - [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-ce/issues/2772

See merge request !8013

Merge Request - https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/8013

# Conflicts:
#   db/schema.rb

Add support for nested groups to admin routing

See merge request !8008

Updates the docs to require GitLab Shell 4.0.3

See merge request !8050

Detailed build statuses

## What does this MR do?

Implements detailed statuses for `Ci::Builds` and `CommitStatus`.

It also adds a new icon for manual build.

## Screenshots

![manual_builds_icon](/uploads/22b5c594350856c85398ef705a635f8b/manual_builds_icon.png)

## What are the relevant issue numbers?

See #24273, closes #22642

See merge request !7989

Fix wrong error message expectation in API::Commits spec

See commit message or https://gitlab.com/gitlab-org/gitlab-ce/issues/25651#note_19996076 for the explanation.

Closes #25651

See merge request !8083

Encode when migrating ProcessCommitWorker jobs

## What does this MR do?

This adds encoding logic to the migration for ProcessCommitWorker, ensuring it doesn't throw errors when the input can not be converted to UTF-8 without extra help.

## What are the relevant issue numbers?

https://gitlab.com/gitlab-org/gitlab-ce/issues/25489

See merge request !8064

Fix broken link for latest deployment

## What does this MR do?

Creates a new helper for the latest deployment link.

## Why was this MR needed?

A helper that returns a link was being called inside another helper that creates a link, resulting in  `builds/<a href="builds/ID>#id</a>`

## What are the relevant issue numbers?

Closes #25136

See merge request !7839

This was because the MR was a bit behind master and the error message
got updated in the meantime by 79aad815.
Signed-off-by: Rémy Coutable <remy@rymai.me>