Part of https://gitlab.com/gitlab-org/gitlab-ce/issues/24899

See https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/7779 and
https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/7813

Pipelines tabs

## What does this MR do?
Changes the URL when the builds tab is clicked making it possible to be shared.

1. Adds a standard way to handle linked tabs:
    *   This behaviour is already present in the merge requests, commit and user `show` page. 
    *    This MR introduces a reusable way to accomplish this behaviour for pages with static content.

2. Adds test:
    *   For the linked tabs reusable class
    *  For the pipelines tabs

## Why was this MR needed?
To allow having a sharable URL that represented the opened tab

![tabs](/uploads/91e663c12c6e9ac46a17aa3a9489dc72/tabs.gif)

## 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 #24814

See merge request !7709

Remove the help text under the sidebar subscribe button and style it inline

## What does this MR do?

Remove the help text under the sidebar subscribe button and style it inline

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


## Why was this MR needed?
Current help text is over obvious and pushes references too far down. Also the subscribe button is now consistently styled and not a complete block button anymore. approved by @awhildy 

## Screenshots (if relevant)

before:
![image](/uploads/0c9543d2bf184a73b65773caa5f9fc62/image.png)

after:
![image](/uploads/765338823376267427f4a16737e39998/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
- [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 #24281

See merge request !7389

Resolve "missing design for wiki page"

### To Do:

- [x] Move page navigation from sub-menu to sidebar menu
- [x] Update wiki page header
- [x] Update wiki edit page actions and header
- [x] Update `Git access` page design
- [ ] ~~Add search to sidebar navigation~~

### Screen Shots:

#### `@media (min-width: $screen-lg)`

![Screen_Shot_2016-11-16_at_12.25.47_PM](/uploads/2efc59639ac53d69808e78a8ba65fcbf/Screen_Shot_2016-11-16_at_12.25.47_PM.png)  
![Screen_Shot_2016-11-16_at_12.25.36_PM](/uploads/bb7e93558335edf4216082cc1ac3f8f5/Screen_Shot_2016-11-16_at_12.25.36_PM.png)  
![Screen_Shot_2016-11-16_at_12.26.43_PM](/uploads/c2dce7cff05680b9a03438ec7d9967b4/Screen_Shot_2016-11-16_at_12.26.43_PM.png)  
![Screen_Shot_2016-11-16_at_12.26.05_PM](/uploads/7dbae25bfc93fb2f01cd231db0cb47d3/Screen_Shot_2016-11-16_at_12.26.05_PM.png) 

#### `@media (min-width: $screen-md)`

![Screen_Shot_2016-11-16_at_12.28.18_PM](/uploads/4fdcc8c88c38093ea5a4fe0b22b79acf/Screen_Shot_2016-11-16_at_12.28.18_PM.png)  
![Screen_Shot_2016-11-16_at_12.28.21_PM](/uploads/ce84a51fdc0623b2b192d8334c2c2f6d/Screen_Shot_2016-11-16_at_12.28.21_PM.png)  

#### `@media (min-width: $screen-sm)`

![Screen_Shot_2016-11-16_at_12.28.05_PM](/uploads/cf612a36259c248ca597a0850546fe75/Screen_Shot_2016-11-16_at_12.28.05_PM.png)  
![Screen_Shot_2016-11-16_at_12.28.08_PM](/uploads/ae4374f9968c1cc064242fde3ad0e214/Screen_Shot_2016-11-16_at_12.28.08_PM.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)
- 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 #18546

See merge request !7429

Signed-off-by: Rémy Coutable <remy@rymai.me>

Fix pipelines tests

Fix rubocop

Moves matches poly to the correct file
Divides pipelines index and show tests in order to be able to test with JS