Fix some N+1s when calculating notification recipients

Closes #45534

See merge request gitlab-org/gitlab-ce!19535

Resolve "Navbar is broken on mobile"

Closes #47504

See merge request gitlab-org/gitlab-ce!19550

Fixes IDE button on merge requests not working with relative URL config

Closes #46438

See merge request gitlab-org/gitlab-ce!19546

Add git filter flag only if it is supported

See merge request gitlab-org/gitlab-ce!19529

Resolve "Hashed Storage: Make possible to migrate single project"

Closes #46922

See merge request gitlab-org/gitlab-ce!19268

Resolve "Add `label-light` class to labels for new kubernetes cluster form"

Closes #47432

See merge request gitlab-org/gitlab-ce!19499

Resolve "Performance bar select box has wrong text colour"

See merge request gitlab-org/gitlab-ce!19523

Consistently use tar lookup function

See merge request gitlab-org/gitlab-ce!19477

Add artifacts expiry time for GitLab.com

See merge request gitlab-org/gitlab-ce!19520

Add installation type to usage ping data

See merge request gitlab-org/gitlab-ce!19300

Make request argument required for Applications::CreateService

See merge request gitlab-org/gitlab-ce!19530

Update doc for maintaining project visibility during Github import

Closes #47189

See merge request gitlab-org/gitlab-ce!19533

Closes #46438

Docs: index article

See merge request gitlab-org/gitlab-ce!19544

Port the Auto DevOps docs from EE

See merge request gitlab-org/gitlab-ce!19539

Backport of 5942-extract-ee-specific-files

See merge request gitlab-org/gitlab-ce!19285

Docs: article - Deploy SB apps to CF with GitLab CI/CD

Closes #47505 and #37524

See merge request gitlab-org/gitlab-ce!19540

[CE] Resolve "Extract EE specific files/lines for app/views/admin/groups"

Closes gitlab-ee#6216

See merge request gitlab-org/gitlab-ce!19275

Merge branch '47470-gke-cluster-creation-form-has-project-id-label-for-project-name-field' into 'master'

Resolve "GKE cluster creation form has 'project id' label for 'project name' field"

Closes #47470

See merge request gitlab-org/gitlab-ce!19528

Restore navigation theme order

See merge request gitlab-org/gitlab-ce!19521

Resolve "Update docs to reflect the new place of the Kubernetes page"

Closes #46404

See merge request gitlab-org/gitlab-ce!19524

Stop logging email information when emails are disabled

Closes #44790

See merge request gitlab-org/gitlab-ce!18521

First N+1: we may have loaded a user's notification settings already, but not
have loaded their sources. Because we're iterating through, we'd potentially
load sources that are completely unrelated, just because they belong to this
user.

Second N+1: we do a separate query for each user who could be subscribed to or
unsubcribed from the target. It's actually more efficient in this case to get
all subscriptions at once, as we will need to check most of them.

We can fix both by the slightly unpleasant means of checking IDs manually,
rather than object equality.