Respect the `should_remove_source_branch` parameter to the merge API

Closes #58020

See merge request gitlab-org/gitlab-ce!25525

Compute approved approver for merged MR if it is absent

Closes #9866, #9889, and #9913

See merge request gitlab-org/gitlab-ee!9648

Past merged MRs do not have approved_approvers for now,
so to keep UI display correctly, compute approved approvers if
association is empty.

Recreate fail case as spec to test creation of `approved_approver`
after merge. Use `inverse_of` to ensure same copy of MR object across
`PostMergeService` and `ApprovalMergeRequestRule`. This means we can
avoid reloading `approval_rules` to solve outdate MR merge state issue.

Project template for .NET

Closes #57794

See merge request gitlab-org/gitlab-ce!25486

Merge branch '57794-project-template-for-net' of https://gitlab.com/gitlab-org/gitlab-ce into 57794-project-template-for-net

CE Allow Gitaly N+1 in MR CreationsController

See merge request gitlab-org/gitlab-ce!25499

Resolve "Project import error, User expected, got Hash"

Closes #57712

See merge request gitlab-org/gitlab-ce!25495

Resolve "Styling of user, project and group avatars"

Closes #52734

See merge request gitlab-org/gitlab-ce!25098

- Add rectangular avatar classes
- Update avatar for groups
- Update avatar for projects
- Update avatar for frequent items
- Update avatar on "Fork project" page
- Conditionally add rectangular avatar class to autocomplete items

Remove unnecessary difference between CE and EE

Closes #58070

See merge request gitlab-org/gitlab-ce!25513

Delegate last_pipeline to Project

See merge request gitlab-org/gitlab-ce!25422

"Cross-Project Pipeline Dashboard MVC" backend

See merge request gitlab-org/gitlab-ee!9396

Allow maintainers to remove pages

See merge request gitlab-org/gitlab-ce!25458

Move remove_pages permission to maintainer
Fix before_action in pages controller to check `remove_pages`
permission
Add specs

Expose refspec and depth to runner

See merge request gitlab-org/gitlab-ce!25233

Docs: update code review guidelines

Closes #57305

See merge request gitlab-org/gitlab-ce!25460

Refactor note target override for Epics

Closes #9949

See merge request gitlab-org/gitlab-ee!9686

Add ability to set project path and name on fork using API

Closes #40795

See merge request gitlab-org/gitlab-ce!25363

Make Admin::UsersController work with Ruby 2.6

See merge request gitlab-org/gitlab-ce!25316

Allow configuring POSTGRES_VERSION in Auto DevOps

Closes #58098

See merge request gitlab-org/gitlab-ce!25500

Resolve "Don't display pipeline status if pipelines are disabled"

Closes #52778

See merge request gitlab-org/gitlab-ce!25204

Pipeline status was showing failed on projects when CI was disabled.

This checks to see if the feature is enabled before showing the status.

Properly implement API pagination headers and add specs

Closes #57684

See merge request gitlab-org/gitlab-ce!25267

Ability to filter confidential issues

Closes #50747

See merge request gitlab-org/gitlab-ce!24960

(EE port) Resolve "Styling of user, project and group avatars"

See merge request gitlab-org/gitlab-ee!9682

- Add rectangular avatar classes
- Update avatar for groups
- Update avatar for projects
- Update avatar for frequent items
- Update avatar on "Fork project" page
- Conditionally add rectangular avatar class to autocomplete items

API endpoint for bulk updating issues and MRs

Closes #49449

See merge request gitlab-org/gitlab-ce!25201

Fix misspellings in app/spec comments

See merge request gitlab-org/gitlab-ce!25517