[EE] Update API spec files to describe the correct class

Port of gitlab-org/gitlab-ce!7718 to EE.

See merge request !940

Include note about using user_filter syntax with special chars

Fixes https://gitlab.com/gitlab-org/gitlab-ee/issues/1201

See merge request !882

CE upstream merge

- [x] .gitlab-ci.yml
- [x] Gemfile.lock
- [x] app/assets/stylesheets/pages/issuable.scss
- [x] app/controllers/concerns/lfs_request.rb
- [x] app/controllers/projects/git_http_controller.rb
- [x] app/helpers/issuables_helper.rb
- [x] app/models/concerns/protected_branch_access.rb
- [x] app/models/protected_branch/merge_access_level.rb
- [x] app/models/protected_branch/push_access_level.rb
- [x] app/services/system_note_service.rb
- [x] app/views/shared/issuable/_filter.html.haml
- [x] app/views/shared/issuable/_form.html.haml
- [x] app/views/shared/issuable/form/_metadata.html.haml
- [x] db/schema.rb
- [x] doc/web_hooks/web_hooks.md
- [x]  features/steps/project/wiki.rb
- [x] lib/api/projects.rb
- [x] lib/gitlab/git_access.rb
- [x] spec/features/security/project/private_access_spec.rb
- [x] spec/features/security/project/public_access_spec.rb
- [x] spec/mailers/notify_spec.rb
- [x] spec/services/merge_requests/merge_service_spec.rb
- [x] spec/services/merge_requests/refresh_service_spec.rb
- [x] spec/services/projects/destroy_service_spec.rb

Merged changes https://gitlab.com/gitlab-org/gitlab-ce/compare/858602ea153056f6cbfeeb4114ea6e29aba03a7a...14046b9c734e5e6506d63276f39f3f9d770c3699

See merge request !937

Prevent remote mirrors from failing when project is in pending_delete

We noticed on GitLab.com that remote mirrors were not even running.
UpdateAllRemoteMirrorsWorker was failing on a project that was in
pending_delete, preventing any workers from running.

Closes gitlab-org/gitlab-ce#23650

See merge request !938

The models were incorrectly merged (this would have been avoided if !927
was merged in, but that MR is still review) leading to a few spec failures.

We noticed on GitLab.com that remote mirrors were not even running.
UpdateAllRemoteMirrorsWorker was failing on a project that was in
pending_delete, preventing any workers from running.

Closes gitlab-org/gitlab-ce#23650

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

Restore changes for api spec files

Fix error in rspec Users

Delete extra space Repositories-spec

Speed up project snippet security request specs

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

EE sibling of https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/7890

See merge request !939

Save some queries on issuable dashboard.

EE version of https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/7760.

See merge request !935

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

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

Instead of doing n queries for n states, do one query to get all the
counts grouped by state, and figure out what the count is for each state
is from that. We can still cache the individual counts (it can't hurt),
but this will help with initial load.

Note that the `opened` scope on `Issuable` includes the `opened` and
`reopened` states, which is why there's a special case.

`any?` on an AR relation performs a `SELECT COUNT`, which we don't need.

1. We are very likely to have issues or MRs, so the `SELECT COUNT` is
   often unnecessary.
2. Even where there are no items returned, the overhead of the
   `SELECT *` instead of `SELECT COUNT` is relatively small.

Calling `to_a` on the relation lets us use `Enumerable#any?`, which will
return immediately if there are objects returned.

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