Replace MR access checks with use of MergeRequestsFinder

Split from !2024 to partially solve https://gitlab.com/gitlab-org/gitlab-ce/issues/23867

:warning: - Potentially untested
:bomb: - No test coverage
:traffic_light: - Test coverage of some sort exists (a test failed when error raised)
:vertical_traffic_light: - Test coverage of return value (a test failed when nil used)
:white_check_mark: - Permissions check tested

- [x] :bomb:  app/finders/notes_finder.rb:17
- [x] :warning:  app/views/layouts/nav/_project.html.haml:80 [`.count`]
- [x] :bomb:  app/controllers/concerns/creates_commit.rb:84
- [x] :traffic_light:  app/controllers/projects/commits_controller.rb:24
- [x] :traffic_light:  app/controllers/projects/compare_controller.rb:56
- [x] :vertical_traffic_light:  app/controllers/projects/discussions_controller.rb:29
- [x] :white_check_mark:  app/controllers/projects/todos_controller.rb:27
- [x] :vertical_traffic_light:  app/models/commit.rb:268
- [x] :white_check_mark: lib/gitlab/search_results.rb:71

- [x] https://dev.gitlab.org/gitlab/gitlabhq/merge_requests/2024/diffs#d1c10892daedb4d4dd3d4b12b6d071091eea83df_267_266 Memoize ` merged_merge_request(current_user)`
- [x] https://dev.gitlab.org/gitlab/gitlabhq/merge_requests/2024/diffs#d1c10892daedb4d4dd3d4b12b6d071091eea83df_248_247 Expected side effect for `merged_merge_request!`, consider `skip_authorization: true`.
- [x] https://dev.gitlab.org/gitlab/gitlabhq/merge_requests/2024/diffs#d1c10892daedb4d4dd3d4b12b6d071091eea83df_269_269 Scary use  of unchecked `merged_merge_request?`

See merge request !2033

counter

This is done by:
 - Extending the IssuableFinder adding the non_archived option to the params
 - Overriding the #filter_params in the MergeRequestsAction
 - Passing the non_archived param in the nav/_group.html.haml navbar
   partial from the groups/merge_requests.html.haml

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

Also create a new WorkhorseRequest concern

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

Backport some changes done from Time Tracking feature in EE.

See merge request !7604

Cycle Analytics: Events per stage

Adds list of events to each stage:

- Issue: list of issues created in the last XX days, that have been labeled or added to a milestone.
- Plan: list of commits that reference for the fist time an issue from the last stage.
- Code: list of MR created in this stage
- Test: List of unique builds triggered by the commits.
- Review: List of MR merged
- Staging: List of deployed builds
- Production: list of issues with the time from idea to production

Fixes #23449 

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

See merge request !6859

More aggressively preload on merge request and issue index pages

See merge request !7564