CE->EE merge before 8.13.0-rc1

Conflicts resolved in the first merge:

```
UU app/models/group.rb
UU app/models/member.rb
UU app/models/project_team.rb
UU app/services/merge_requests/update_service.rb
UU app/services/notification_service.rb
UU app/views/shared/_sort_dropdown.html.haml
UU doc/api/oauth2.md
UU lib/api/members.rb
UU spec/models/merge_request_spec.rb
AA spec/views/ci/lints/show.html.haml_spec.rb
UU app/views/projects/commits/_head.html.haml
```

Conflicts resolved in the second merge:

```
UU app/assets/javascripts/groups_select.js
UU app/assets/javascripts/labels_select.js
UU app/controllers/concerns/membership_actions.rb
UU app/controllers/groups/group_members_controller.rb
UU app/helpers/selects_helper.rb
UU app/views/admin/dashboard/index.html.haml
UU app/views/shared/issuable/_form.html.haml
UU app/views/shared/issuable/_label_dropdown.html.haml
UU app/views/shared/issuable/_sidebar.html.haml
UU config/routes.rb
UU spec/services/merge_requests/merge_service_spec.rb
UU spec/services/system_note_service_spec.rb
```

See merge request !772