This is justified because even at the MAX_ISSUE_COUNT, we would only
ever use 0.1% of the full range width by assuming this value. Extremely
large projects such as gitlab-org/gitlab have on the order of around
100k issues, and would only need 1% of the full range.

We can thus assume such a value as gap_size even allowing for 10x growth
in gitlab's issue numbers, at which point managing locking and
concurrent updates during rebalancing would be a much more challenging
problem.

This moves the issue presence check to the first place (as it should be)
and doesn't check for feature availability until we know we need to.

This involves a refactoring of the service so that it is less of a
single procedural thicket.

Safer use of flags, by checking them in the service and the worker.

Allow groups to be used as feature flag gates.

This adds a new feature flag: `rebalance_issues`

This flag is scoped by project, and is read in the issue create and
update services.

This adds a new method in the issues base_service that rebalances the
issue set when the issue is placed in the extreme 0.0001 fringes of the
relative positioning range.

This adds the required worker queue definition for sidekiq, with its
configuration and generated defintion.

Remove git ignored schema_migration files

See merge request gitlab-org/gitlab!40291

Merge branch '872-merge-glskeletonloading-into-glskeletonloader-gitlab-ui-integration-test' into 'master'

GitLab UI: 872-merge-glskeletonloading-into-glskeletonloader integration test

See merge request gitlab-org/gitlab!38663

Bump marginalia gem version to 1.9.0

See merge request gitlab-org/gitlab!40481

Extract page specific styles todos

See merge request gitlab-org/gitlab!38890

Instead of using globbing and because we want to move these page
specific styles to the appropriate pages, we move the imports to a new
file.

Fix Long Content Collapses Icons in Vulnerability Comment

Closes #234085

See merge request gitlab-org/gitlab!40407

Add pipeline_artifacts_size to root_storage_statistics

See merge request gitlab-org/gitlab!40425

Remove users.bio column

Closes #226989

See merge request gitlab-org/gitlab!40269

Allow snippet move actions without an existing file name

See merge request gitlab-org/gitlab!40343

Doc - remove outdated message

See merge request gitlab-org/gitlab!40373

Count security jobs

See merge request gitlab-org/gitlab!39481

Add version history to distributed reads

See merge request gitlab-org/gitlab!39793

Add more US spelling rules

See merge request gitlab-org/gitlab!40204

Scope down Chrome version for icon fix

See merge request gitlab-org/gitlab!40526

To account for changes to `GLSkeletonLoader`

The main change is the addressed Ruby 2.7 warnings

Wrap dashboards dropdown items text

See merge request gitlab-org/gitlab!40367

Add button to return to merge request on pipeline celebration

Closes #230497 and #223110

See merge request gitlab-org/gitlab!37393