Validate user id for users select autcomplete

## What does this MR do?

Adds digit validation to user_id when build user autocomplete URL for select2. 

## Why was this MR needed?

To prevent building invalid URL for non existing users like  GET "/autocomplete/users/whatever@example.com.json".

As result it fixes failing test:

```
Feature: Admin Groups

  Scenario: Invite user to a group by e-mail
    ✔  Given I sign in as an admin                                                             # features/steps/shared/authentication.rb:11
    ✔  And I have group with projects                                                          # features/steps/admin/groups.rb:17
    ✔  And User "John Doe" exists                                                              # features/steps/shared/user.rb:4
    ✔  And I visit admin groups page                                                           # features/steps/shared/paths.rb:194
    ✔  When I visit admin group page                                                           # features/steps/admin/groups.rb:9
    ✔  When I select user "johndoe@gitlab.com" from user list as "Reporter"                    # features/steps/admin/groups.rb:48
    ✔  Then I should see "johndoe@gitlab.com" in team list in every project as "Reporter"      # features/steps/admin/groups.rb:63
/Users/dzaporozhets/.rvm/gems/ruby-2.3.1/gems/actionpack-4.2.7.1/lib/action_dispatch/middleware/debug_exceptions.rb:21:in `call': No route matches [GET] "/autocomplete/users/johndoe@gitlab.com.json" (ActionController::RoutingError)
```

See merge request !6889

Single user autcomplete should be used only for existing users with
digital ID provided. Now js code puts any input into generating user URL
which can lead to 500 error because routing like this does not exists:

GET "/autocomplete/users/whatever@example.com.json".
Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Add missing routes to make group edits work

6b90ccb9 changed the routes so that users/groups can be accessed via`/:id`, but the Rails `form_for` method expects to use the `groups#show` path helper for the form action URL. This causes group edits and deletes to fail because the PUT/PATCH/DELETE methods did not exist for `/:id`.  This MR adds these methods so that `form_for` continues to work.

Closes #23306 


See merge request !6874

Project members UI

## What does this MR do?

New UI for project members that includes groups.

## Screenshots (if relevant)


### Project members

![Screen_Shot_2016-09-02_at_15.13.27](/uploads/b9d4a634d44b7b7bbb6eddb10aee86bd/Screen_Shot_2016-09-02_at_15.13.27.png)

### Group members

![Screen_Shot_2016-09-02_at_15.13.36](/uploads/c15c173e68b2c0b49bcd06ca560269d3/Screen_Shot_2016-09-02_at_15.13.36.png)

## What are the relevant issue numbers?

Part of #19868 

Closes #21320 

See merge request !6148

Added 'No template' functionality to issuable templates

## What does this MR do?

Adds dropdown new footer item `.no-template`, when clicked it clears the `currentTemplate`, updates the editor and resets the dropdown toggle text.

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

## Why was this MR needed?

## Screenshots (if relevant)

![2016-10-10_03.21.45](/uploads/86ae95410807c66ce7b8be63c7ec2c20/2016-10-10_03.21.45.gif)

## 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
- [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 #22456

See merge request !6765

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

Grapify boards API

## What does this MR do?

Add the Grape-DSL to the boards API.

## What are the relevant issue numbers?

Related to #22928

See merge request !6876

Updated issuable dropdown titles

## What does this MR do?

The dropdowns in the issuable form still had the filter dropdown titles, this fixes that by giving them their own titles.

Closes #23337

See merge request !6882

Fix grafana_configuration.md move link

See merge request !6871

Show deployed time ago

Closes #21652

cc @ayufan 

See merge request !6676

Reassign secret token when regenerating one

## What does this MR do?

This is an attempt to fix intermittent errors in out test suite.

```text
Failures:

  1) Gitlab::Shell memoized secret_token creates and links the secret token file
     Failure/Error: expect(File.read(secret_file).chomp).to eq(secret_token)
     
       expected: "690f959e206ab91acc54e1c605c7ff90"
            got: "cccb4e8df9360600271e61114d4e6e68"
     
       (compared using ==)
     # ./spec/lib/gitlab/backend/shell_spec.rb:47:in `block (3 levels) in <top (required)>'
```

It appears that `spec/lib/gitlab/backend/shell_spec.rb` tries to change the file that stores secret token, but `Gitlab::Shell` memoizes `@secret_token` on class level, so when it was already created by other tests (`spec/requests/api/internal_spec.rb` in this case), memoized token is not reassigned even if it was generated again with `ensure_secret_token!`.

See merge request !6844

Grapify todos API

## What does this MR do?

Add the Grape-DSL to the todos API.

## What are the relevant issue numbers?

Related to #22928

See merge request !6875

Extract project#update_merge_requests to its own worker from GitPushService

See merge request !6767

Closes #23337

Resolve "Fix missing Glossary link"

## What does this MR do?

Fixes broken links in University.

## What are the relevant issue numbers?

Closes #23332

See merge request !6880

Grapify system hooks API

## What does this MR do?

Add the Grape-DSL to the system-hook API.

## What are the relevant issue numbers?

Related to #22928

See merge request !6861

Add more info on the new CI permissions model

From discussion in issue https://gitlab.com/gitlab-org/gitlab-ce/issues/22484

See merge request !6843

Refactor merge requests revisions docs

See merge request !6878

- A system note now appears on every push
- Replace dashes with underscores in images

[ci skip]