Enable multipart transfers for S3 copying

See merge request gitlab-org/gitlab!51267

This is a follow-up to
https://gitlab.com/gitlab-org/gitlab/-/merge_requests/50922. Multithreaded,
multipart transfers are only enabled if the file is above 5 GB or the
multipart chunk size is explicitly set.

We now set the chunk size to 10 megabytes (the AWS SDK default) to make
file copies faster.

This commit also updates fog-aws to v3.8.0 to work properly with server
side encryption parameters.

CHANGELOG: https://github.com/fog/fog-aws/blob/master/CHANGELOG.md

Implement declarative enums abstraction

See merge request gitlab-org/gitlab!50698

Update GraphqlExtractor return value to be original hash

See merge request gitlab-org/gitlab!51596

Merge branch '297364-flaky-test-spec-services-merge_requests-export_csv_service_spec-rb-29-mergerequests' into 'master'

test: Fix flaky expectations

See merge request gitlab-org/gitlab!51457

Merge branch '296976-the-open-list-in-boards-with-swimlanes-applied-is-mislabeled-as-backlog' into 'master'

Rename Backlog list to Open for Swimlanes

See merge request gitlab-org/gitlab!51539

Remove merge_ref_auto_sync flag

See merge request gitlab-org/gitlab!51624

Instead of spreading the enum information all around the codebase
between different modules like models and GraphQL types, we can set a
single source of the truth for the Enum values.

To do so, we should promote the enums to be first class members of the
project by giving them a new top level directory to live in.

Remove test_failure_history flag

See merge request gitlab-org/gitlab!51464

Remove github_import_pull_request_reviews feature flag

See merge request gitlab-org/gitlab!51334

Override tertiary button mix blend mode for darkmode

See merge request gitlab-org/gitlab!51349

Reverts !46222 to fix 500 error on project's edit page.

See merge request gitlab-org/gitlab!51662

Update gitlab-experiment to 0.4.5

See merge request gitlab-org/gitlab!51506

This makes two functionally similar but helpful improvements in terms of
more clarity and better behavior when circumventing existing codepaths.

Docs: Clarify merge train requirement for GitLab repo

See merge request gitlab-org/gitlab!51647

Fix issues with IDE commit to new branch

See merge request gitlab-org/gitlab!51654

This reverts commit fcc43e30.

Fix argument type for background migration

See merge request gitlab-org/gitlab!51475

Add Design Sprint Template to issue templates.

See merge request gitlab-org/gitlab!51226

Record action when namespace trial starts

See merge request gitlab-org/gitlab!49351

Add `gl-button` to move issue button in issue sidebar

See merge request gitlab-org/gitlab!51285

- It is important that we update the route to the new
  branch.
- Also, we add a "destroy" event to the root component
  so that the spec can properly dispose of Singleton
  things. Otherwise, specs were bumping into eachother
  because Monaco models were being shared.

This actually caused a number of issues and
left the Web IDE in a broken state.

Trigger empty state only for missing file case

See merge request gitlab-org/gitlab!51653

Merge branch '215309-improve-the-error-message-username-has-already-been-taken-on-user-creation' into 'master'

Improve User username error for namespace conflict

See merge request gitlab-org/gitlab!47537