Diplay correct message in git clients when License is not configured

See merge request !1133

- Allow the message to be returned from git_http controller
- Strip html chars from message returned via API

Squash binary files

See merge request !1174

Elasticsearch: allow initial indexing to proceed within Sidekiq

Closes #1618

See merge request !1144

Prior to this commit, the `index_statuses` table was allowed to go stale after
initial indexing. This made it impossible to provide status details, and also
made treating the initial index as a 'backfill' job harder.

Now, if a repository is indexed via `git push`, the initial indexing will
recognise that it has been indexed, and not re-index it.

We introduce an asynchronous initial indexer and an index status rake task at
the same time.

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

See merge request !1166

Geo: send the new event type with the backfill function

Closes #1645

See merge request !1157

Rugged's `#to_patch` method doesn't generate a patch suitable for binary
files. Instead, piping `git diff --binary` to `git apply` will do this
and avoid allocating strings in Ruby, as an added bonus.

CE upstream

Closes gitlab-ce#27674

See merge request !1170

This commit introduces a `gitlab:elastic:index_repositories_async' rake task,
which can be used to enqueue a set of indexing jobs into Sidekiq. These will
be scheduled in the usual manner, in the `sidekiq` queue.

In theory, this allows Sidekiq's concurrency and distributed execution features
to be used to spread and control the load of indexing repositories.

CE upstream

Closes #395

See merge request !1161

Add index to labels for `type` and project_id`

Closes #27676

See merge request !8978

Fixed typo in slash commands docs

Closes #27674

See merge request !8976

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

See merge request !1168

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