If the Geo check for `secondary?` failed, the `RequestStore` cache would always
be set to `false` but the cache would not actually be used due to the semantics
of the ||= operator. This led to dozens of SQL calls with:

```sql
SELECT  1 AS one FROM "geo_nodes" LIMIT 1
```

This commit fixes the caching to handle boolean values properly.

Closes #1644

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

Fixes gitlab-org/gitlab-ce#27674

UX Guide: Button placement in groups

See merge request !8972

Integrate webpack for frontend asset compilation

Closes #14634

See merge request !7288

Port "Integrate webpack for frontend asset compilation" to EE

See merge request !1138

* master: (54 commits)
  Move project services to new location under Integrations
  Move webhooks to new a location under Integrations
  Fix documentation link in doc/user/project/pages/index.md
  Fixed merge request widget tests
  Small documentation changes and fixes for Geo
  Remove ‘EE-specific’ comments related to Pages feature
  Update specs with new method signatures
  rm_tag now takes a user argument
  Use GitOperationService instead
  Merge remote-tracking branch 'ce/fix-git-hooks-when-creating-file' into master-ce
  Mentioned pages to CE port in project/pages/index.md
  Fixed merge request environment not displaying
  Update guidance on handling shared secrets in HA setup
  Pull EE specific Gitlab::Auth code in to its own module
  Use `add_$role` helper in snippets specs
  Check public snippets for spam
  Keep snippet visibility on error
  Add info on using both push/pull repository mirroring
  Properly read approvalPending from dataset.
  Fix data attr spacing.
  ...