Add traits for ProjectFeatures to Project factory

Closes #24007

See merge request !8925

Update NFS HA doc with location -> config mapping

Closes #27685

See merge request !8993

Added specs for merge request environment list

See merge request !8937

Don't render snippet actions for logged-out users

Closes #27708

See merge request !8995

Resolve "Remove hover animation from row elements"

Closes #26863

See merge request !8842

V4 API: Remove deprecated MR and Issue endpoints and preserve V3 namespace

Closes #27180

See merge request !8967

Make all system notes lowercase

See merge request !8807

Modify the search bar area on admin/projects page

Closes #26794

See merge request !8776

Resolves user avatar flickers as you type

Closes #27602

See merge request !8950

Use babel to transpile all non-vendor javascript assets regardless of file extension

See merge request !8988

fix ace editor modules to include asset digest in production

See merge request !8869

Introduce maximum session time for terminal websocket connection

Closes #26263

See merge request !8413

Unify projects search by removing /projects/:search endpoint

Closes #22007

See merge request !8877

API: Fix file downloading

See merge request !8953

Store the value in application settings.
Expose the value to Workhorse.

Add index to labels for `type` and project_id`

Closes #27676

See merge request !8978

https://gitlab.com/gitlab-org/gitlab-ce/issues/24007

Fixed typo in slash commands docs

Closes #27674

See merge request !8976

When loading pages that display the number of open issues,
the backend runs a query such as:

```sql
SELECT "labels"."id" FROM "labels" WHERE "labels"."type" IN ('ProjectLabel') AND "labels"."project_id" = 1000
```

This results in an entire scan of the `labels` table. To optimize performance,
add the appropriate index to the table.

Closes #27676

Fix "NameError: uninitialized constant Rack::Proxy" in production environment

See merge request !8977

Fixes gitlab-org/gitlab-ce#27674

UX Guide: Button placement in groups

See merge request !8972