Multiple environments support for feature flags (Unleash API standpoint)

See merge request gitlab-org/gitlab-ee!9110

Update Helm to 2.12.2 to address Helm client vulnerability

Closes #56417

See merge request gitlab-org/gitlab-ce!24418

Externalize strings from `/app/views/sent_notifications`

See merge request gitlab-org/gitlab-ee!9261

Merge branch '56731-wait_for_job_to_be_done-gitlab-assets-compile-fails-in-the-review-build-cng-job' into 'master'

Resolve "`wait_for_job_to_be_done "gitlab:assets:compile"` fails in the `review-build-cng` job"

Closes #56731

See merge request gitlab-org/gitlab-ce!24598

Fix closing Markdown codeblock in Epics API docs

See merge request gitlab-org/gitlab-ee!9257

Resolve "Changing wording to "Delete" when referring to removing a branch"

Closes #25569

See merge request gitlab-org/gitlab-ce!23966

Add troubleshooting section to Slack Notification Service

See merge request gitlab-org/gitlab-ce!24339

Signed-off-by: Rémy Coutable <remy@rymai.me>

Fix bug that caused Suggestion Markdown toolbar button to insert snippet with leading +/-/<space>

See merge request gitlab-org/gitlab-ce!24568

Add Avatar in the settings sidebar

Closes #56582

See merge request gitlab-org/gitlab-ce!24515

Support for Unleash API

Elaborate a comment in has environment scope

Fix specs

Complete test for unleash API

Add changelog

Fix coding offence

Fix coding offence

Fix ee specific line check

Fix MySQL problem

Fix typo

Improve comment

Fix spec location

Override active value with alias

Add test and feature flag

Add frozen string literal

Default enable true

Decouple default scope related things

Decouple FeatureFlagsFinder change

Fix unleash api app name handling

Add helper for feature flag tests

Reorder columns

All review jobs should share the same only & except

Closes #56707

See merge request gitlab-org/gitlab-ce!24579

Fix serverless.yml template indentation

See merge request gitlab-org/gitlab-ce!24548

Avoid installing Bundler 2.0 or higher on source-based install

Closes #55979

See merge request gitlab-org/gitlab-ce!24502

Fix Red Master For CE !24554

See merge request gitlab-org/gitlab-ee!9266

Rename entrypoint for clusters update/edit page

Closes #56715

See merge request gitlab-org/gitlab-ce!24583

Upgrade Prettier to v1.16

See merge request gitlab-org/gitlab-ce!24581

Upgrade babel to v7.3

See merge request gitlab-org/gitlab-ce!24573

Add domain field into Clusters::Cluster

See merge request gitlab-org/gitlab-ce!24368

For the stake of standardizing, I've switched the ssl debugging to use
the Rails console rather than a Ruby script file.

Offer more explanation regarding the ssl-test script and how it's used.