Add an index to the `file_store` column on `lfs_objects`. This makes
counting local objects faster.

Also, there is no longer need to check for objects with `file_store`
being `NULL`. See
https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/18557

---

### Query plans

#### Before & with `NULL`

```
Aggregate  (cost=113495.96..113495.97 rows=1 width=8) (actual time=1691.394..1691.394 rows=1 loops=1)
  ->  Seq Scan on lfs_objects  (cost=0.00..106415.50 rows=2832186 width=0) (actual time=0.012..1312.488 rows=2852607 loops=1)
        Filter: ((file_store = 1) OR (file_store IS NULL))
        Rows Removed by Filter: 131
Planning time: 0.077 ms
Execution time: 1691.433 ms
```

#### Before, without `NULL`

```
Aggregate  (cost=113495.96..113495.97 rows=1 width=8) (actual time=856.423..856.424 rows=1 loops=1)
  ->  Seq Scan on lfs_objects  (cost=0.00..106415.50 rows=2832186 width=0) (actual time=0.012..672.181 rows=2852607 loops=1)
        Filter: (file_store = 1)
        Rows Removed by Filter: 131
Planning time: 0.128 ms
Execution time: 856.470 ms
```

#### After & with `NULL`

```
Aggregate  (cost=68819.95..68819.96 rows=1 width=8) (actual time=583.355..583.355 rows=1 loops=1)
  ->  Index Only Scan using index_lfs_objects_on_file_store on lfs_objects  (cost=0.43..61688.35 rows=2852643 width=0) (actual time=0.028..399.177 rows=2852607 loops=1)
        Filter: ((file_store = 1) OR (file_store IS NULL))
        Rows Removed by Filter: 131
        Heap Fetches: 867
Planning time: 0.096 ms
Execution time: 583.404 ms
```

#### After, without `NULL`

```
Aggregate  (cost=68817.29..68817.30 rows=1 width=8) (actual time=490.550..490.551 rows=1 loops=1)
  ->  Index Only Scan using index_lfs_objects_on_file_store on lfs_objects  (cost=0.43..61685.68 rows=2852643 width=0) (actual time=0.040..311.760 rows=2852607 loops=1)
        Index Cond: (file_store = 1)
        Heap Fetches: 831
Planning time: 0.294 ms
Execution time: 490.590 ms
```

Closes https://gitlab.com/gitlab-org/gitlab-ee/issues/6067

Fix problem with spec that showed up in EE merge

See merge request gitlab-org/gitlab-ce!22675

docs: Add deprecation notice for renamed licensed feature

See merge request gitlab-org/gitlab-ce!22575

Added a note about machine types

See merge request gitlab-org/gitlab-ce!22572

Update gitlab-ui to 1.9.0

See merge request gitlab-org/gitlab-ce!22632

Remove mousetrap-rails gem

Closes #53270

See merge request gitlab-org/gitlab-ce!22647

Make new merge request URL more friendly when pushing code

Closes #53012

See merge request gitlab-org/gitlab-ce!22526

Add e2e test to push using a private token

See merge request gitlab-org/gitlab-ce!22628

Update moment to 2.22.2

Closes #53273

See merge request gitlab-org/gitlab-ce!22648

Update GitLab Pages to v1.3.0

See merge request gitlab-org/gitlab-ce!22666

Replace deprecated uniq on a Relation with distinct

See merge request gitlab-org/gitlab-ce!22625

Rename 'sast_container' licensed feature

See merge request gitlab-org/gitlab-ce!22662

Upgrade whitequark/parser to 2.5.3.0

See merge request gitlab-org/gitlab-ce!22652

Delete job_spec.js

See merge request gitlab-org/gitlab-ce!22664

Tests pushing over HTTP(S) using a personal access token

Truncate milestone title on collapsed sidebar

See merge request gitlab-org/gitlab-ce!22624

[11.4] Fix Token lookup for Git over HTTP and registry authentication

See merge request gitlab/gitlabhq!2577

Fix broken "Show whitespace changes" button on MR "Changes" tab

Closes #52122

See merge request gitlab-org/gitlab-ce!22539

[master] Escape issue title while template rendering to prevent XSS

See merge request gitlab/gitlabhq!2556

[master] Redact unsubscribe links in issuable texts

See merge request gitlab/gitlabhq!2528

[master] Resolve "Sensitive information is stored in browser history"

See merge request gitlab/gitlabhq!2555

[master] Validate Wiki attachments are valid temporary files

See merge request gitlab/gitlabhq!2568

[master] JUnit test reports endpoint exposes full stack trace in production mode

See merge request gitlab/gitlabhq!2559

[master] Persist only SHA digest of PersonalAccessToken#token

See merge request gitlab/gitlabhq!2498

[master] Fix XSS in MR source branch name

See merge request gitlab/gitlabhq!2544

[master] Prevent SSRF attacks in HipChat integration

See merge request gitlab/gitlabhq!2530

Remove all tables from Pipeline page when there is no job for the Pipeline

Closes #45669

See merge request gitlab-org/gitlab-ce!18540

Extract ee specific lines for issues and mr controllers

See merge request gitlab-org/gitlab-ce!22569

Fix open-ended params for api_json.log

Closes #53155

See merge request gitlab-org/gitlab-ce!22623