Resolve "Deleting a user shouldn't delete associated records"

Closes #28695 and #30514

See merge request !10467

Show the test coverage if it is available

Closes #27911

See merge request !10381

Multi-level container registry images

Closes #17801

See merge request !10109

Use config.toml to configure Gitaly

See merge request !10496

1. Have `MigrateToGhostUser` be a service rather than a mixed-in module, to keep
   things explicit. Specs testing the behavior of this class are moved into a
   separate service spec file.

2. Add a `user.reported_abuse_reports` association to make the
   `migrate_abuse_reports` method more consistent with the other `migrate_`
   methods.

Resolve "Add system note icons to profile page"

Closes #29128

See merge request !10387

Merge commit '46e4ed6b' into feature/multi-level-container-registry-images

* commit '46e4ed6b': (28 commits)
  Award emoji button smiley animation
  Introduced empty/error UX states to environments monitoring.
  Github import rake task
  Remove individual modal width styles
  Fix RuboCop for removing index
  Link to docs site for file in doc/
  Disable invalid service templates (again)
  Show CI status as Favicon on Pipelines, Job and MR pages
  STL file viewer
  Wait for the PDF to be loaded before doing anything
  remove unnecessary lease as cron job
  Search for opened MRs - include reopened  MRs
  ProjectsFinder should handle more options
  Clearly show who triggered the pipeline in email
  Make it possible to preview pipeline success/failed emails
  Add remove_concurrent_index to database helper
  Add more tests for subgroups feature
  Large features by the 1st, small ones by the 3rd
  Ask people to create EE MRs on the 7th
  fix project authorizations migration issue
  ...

Linking to edit file directly

Closes #28899

See merge request !10233

Recent search history for issues

Closes #27262

See merge request !10324

Optimise trace handling code to use streaming instead of full read

See merge request !10311

Support 2FA requirement per-group

See merge request !8763

Fixes https://gitlab.com/gitlab-org/gitlab-ce/issues/27262

Use Gitaly for Environment#first_deployment_for

See merge request !10294

Include endpoint in metrics for ETag caching middleware

See merge request !10495

Resolve "Make modal sizes consistent and mobile friendly"

Closes #29470

See merge request !10088

Fixed user profile tabs causing the page to scroll

Closes #30338

See merge request !10405

Disable invalid service templates (again)

Closes #30024

See merge request !10339

Ask people to create EE MRs on the 7th

See merge request !10371

Add more tests for subgroups feature

See merge request !10486

Prevent Trigger action buttons from wrapping

Closes #29807

See merge request !10186

Award emoji button smiley animation

See merge request !10130

... when the user is destroyed.

1. Normally, for a given awardable and award emoji name, a user is only allowed
   to create a single award emoji.

2. This validation needs to be removed for ghost users, since:

   - User A and User B have created award emoji - with the same name and against
     the same awardable
   - User A is deleted. Their award emoji is moved to the ghost user
   - User B is deleted. Their award emoji needs to be moved to the ghost user.
     However, this breaks the uniqueness validation, since the ghost user is
     only allowed to have one award emoji of a given name for a given awardable

... when the user is destroyed.

To clarify, this regards abuse reports that the to-be-deleted user has _reported_.

Introduction
------------

1. The foreign key was not explicitly specified on the association.
2. The `AbuseReport` model contains two references to user - `reporter_id` and
   `user_id`
3. `user.abuse_report` is supposed to return the single abuse report where
   `user_id` refers to the given user.

Bug Description
---------------

1. `user.abuse_report` would return an abuse report where `reporter_id` referred
   to the current user, if such an abuse report was present.

2. This implies a slightly more serious bug as well:

   - Assume User A filed an abuse report against User B
   - We have an abuse report where `reporter_id` is User A and `user_id` is User B
   - If User A is updated (`user_a.block`, for example), the abuse report would
     also be updated, such that both `reporter_id` _and_ `user_id` point to User A.

Fix
---

Explicitly declare the foreign key `user_id` in the `has_one` declaration

... when the user is destroyed.

1. When the user is deleted.

2. Refactor out code relating to "migrating records to the ghost user" into a
   `MigrateToGhostUser` concern, which is tested using a shared example.

Introduced empty/error UX states to environments monitoring.

Closes #29212

See merge request !10271

Github import rake task

See merge request !10308