Replace 'Sidekiq::Testing.inline!' with 'perform_enqueued_jobs'

Closes #22991

See merge request gitlab-org/gitlab-ce!20768

Enable frozen strings in lib/banzai/filter/*.rb

See merge request gitlab-org/gitlab-ce!20775

Resolve "Commits page tooltips"

Closes #29278

See merge request gitlab-org/gitlab-ce!20674

Display GPG status on repository and blob pages

Closes #36046

See merge request gitlab-org/gitlab-ce!20524

Pipeline security dashboard: Backport code from EE

See merge request gitlab-org/gitlab-ce!20733

[ci skip]

Enable frozen string in newly added files

See merge request gitlab-org/gitlab-ce!20763

Remove method instrumentation for Banzai filters and reference parsers

See merge request gitlab-org/gitlab-ce!20770

Reducing the memory footprint for the rendering

See merge request gitlab-org/gitlab-ce!20744

Fix rendering issue in admin/pages docs

See merge request gitlab-org/gitlab-ce!20766

Docs: Add a step to install Postgresql related Gems before creating the schema

See merge request gitlab-org/gitlab-ce!20739

Minor typo fix CODE_QUALITY seems to have a `_` in it in .gitlab-ci.yml default…

See merge request gitlab-org/gitlab-ce!20762

Resolve "Credentails used for repository import are visible inside the Sidekiq logs (Background Jobs)"

See merge request gitlab-org/gitlab-ce!20641

Allow feature flag names to be a symbol

See merge request gitlab-org/gitlab-ce!20728

Resolve "Document which API is accessible with CI_JOB_TOKEN"

Closes #48627

See merge request gitlab-org/gitlab-ce!20612

Use title: "Unicorn Metrics available" as in EE

See merge request gitlab-org/gitlab-ce!18620

Excludes a few filters that require more work:

* lib/banzai/filter/image_lazy_load_filter_spec.rb
* lib/banzai/filter/syntax_highlight_filter_spec.rb
* lib/banzai/filter/table_of_contents_filter_spec.rb

Part of #47424

Fix #47379 - Project visibility tooltip

Closes #47379

See merge request gitlab-org/gitlab-ce!20535

Resolve "Deploy Tokens failed to clone LFS repository"

Closes #46869

See merge request gitlab-org/gitlab-ce!20729

Remove unused rugged code that is currently on Gitaly

See merge request gitlab-org/gitlab-ce!20754

Hangouts chat integration

See merge request gitlab-org/gitlab-ce!20290

Fix theme index to match reality

See merge request gitlab-org/gitlab-ce!20772

Update CONTRIBUTING to include Manage team

See merge request gitlab-org/gitlab-ce!20750

Fix gitlab import project load

Closes #48123

See merge request gitlab-org/gitlab-ce!20599

Expose web_url attribute in PipelineBasic and JobBasic

See merge request gitlab-org/gitlab-ce!20703

Resolve "Disable SAML and Bitbucket if OmniAuth is disabled"

Closes #48932

See merge request gitlab-org/gitlab-ce!20608

Resolve "Admin > Runners > Edit page overflows screen"

Closes #49341

See merge request gitlab-org/gitlab-ce!20757

Resolve "Uneven spaces between project page counters"

Closes #46126

See merge request gitlab-org/gitlab-ce!20753

For one README.md file, this instrumentation was adding several seconds and
significant RAM and CPU overhead since these filters often iterate through
all HTML nodes in tight loops.

Relates to #49409

`perform_enqueued_jobs` is a Sidekiq method.
Using this method violates the Dependency inversion principle[0].

This commit replaces `perform_enqueued_jobs` with ActiveJob's abstract
method `perform_enqueued_jobs` in specs.

[0]: https://en.wikipedia.org/wiki/Dependency_inversion_principle

* Remove whitespace to fix rendering of verbose logging -feature-docs in
  gitlab-pages docs.