Prometheus requires a trailing newline in its response.

+ cleanup

metrics wip

This is a step for #29118.

Add a single metric to count successful logins.

Summary types are not supported so remove Collector.  Either
we need to support the summary type or we need to create a
multiprocess-friendly Collector.

Add config to load prometheus and set up the Collector and the
Exporter.

Fix `Gemfile` as current prometheus-client gemspec is missing the
`mmap2` dependency.

Skip loading application settings from the database when migrations are pending

Closes gitlab-ee#2361

See merge request !11842

Style people in issuable search bar

Closes #30468

See merge request !11402

Use throttle when window is resized

Closes #33222

See merge request !11857

Refactor specs for WikiPage services

See merge request !11862

Resolve "Merge conflict resolution removed the newline in the end of file"

Closes #32983

See merge request !11817

Add translations for elapsed time in words

Closes #32747

See merge request !11769

Add optional path parameter and fix tests

Closes #33242

See merge request !11868

SystemCheck library for executing checks from a rake task

See merge request !9173

Fix hard-deleting users when they have authored issues

Closes #33215

See merge request !11855

Various Rails initializers (metrics, sentry, etc) are run before migrations,
which can lead to a mismatch between app/models/application_settings.rb and
schema.

Add section to compile GetText files for source installations

See merge request !11865

Promote blameless culture by using "annotate" instead

See merge request !10378

Simplify test&save actions when setting a service integration

Closes #31511

See merge request !11599

Rephrase to enhance readability and some minor grammar in gitlab_flow.md

See merge request !11767

Use inline source maps for karma

Closes #30996

See merge request !11815

Pipeline show view real time header section

See merge request !11797

Allow admins to delete users from the admin users page

Closes #33207

See merge request !11852

Update GITLAB_SHELL_VERSION

See merge request !11835

fix IE11 error from sentry

Closes #32538

See merge request !11586

Show current user immediately in issuable filters

Closes #22921

See merge request !11630

User-facing changes (fast & easy win)

Add new Rake task to simplify the compilation of PO files

See merge request !11864