Add group level labels

## What does this MR do?

Add group level labels.

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

* `LabelsFinder`
* `Gitlab::Gfm::ReferenceRewriter`
* `Banzai::Filter::LabelReferenceFilter`

## Why was this MR needed?

We'll be adding more feature that allow you to do cross-project management of issues.

## Screenshots (if relevant)

* Group Labels
    ![Group Labels](/uploads/2244c06ad68eae4fb246fb4c81bf8060/2.png)

* Project Labels
    ![Project Labels](/uploads/c5839516d2282b51f7418d9dadbeceb4/1.png)

* Expanded references for group labels when moving issue to another project
    ![Expanded references for group labels when moving issue to another project](/uploads/0c9ab248a8420d4978d59349ae3d42e5/3.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)
- [x] API support added
- Tests
  - [x] 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)
- [x] 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)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?

#19997

See merge request !6425

Remove show_menu_above attribute from issuable dropdowns.

Removes `show_menu_above` attribute form issueable dropdowns so they will drop down.

Fixes #23425 and #23317

See merge request !7001

Refactor project_members_controller_spec

Make tests more readable, DRY and closer to RSpec best practices.

Same as https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/6985 but for project_members_controller_spec now

See merge request !6989

Use Hash rocket syntax to fix cycle analytics under Ruby 2.1

Refers to #23510

See merge request !6977

Its time for 8.14 in master

See merge request !6998

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

Prevent wrong markdown on issue ids when project has Jira service activated

fixes gitlab-org/gitlab-ee#828

See merge request !6728

Bump `omniauth-saml` to 1.7.0

Bump `omniauth-saml` to 1.7.0 to include security fixes and metadata support for IdP auto-configuration.

cc @dblessing @dewetblomerus

See merge request !6997

Merge branch '22457-reset-filters-button-should-be-invisible-when-no-filters-are-active' into 'master'

`Reset filters` link should only be visible when filters are active

## Why was this MR needed?

`Reset filters` link is always visible.

Closes #22457

See merge request !6497

Fixed all related specs and also changed the logic to handle edge cases. This includes exporting and exporting of group labels, which will get associated with the new group (if any) or they will become normal project labels otherwise.

Found other issues to do with not being able to import all labels at once in the beginning of the JSON - code was much simpler when we import all labels and milestones associated to a project first, then the associations will find the already created labels instead of creating them from the associations themselves.