Currently, the only way to migrate pages to zip storage is to manually
run the rake task:

```
gitlab-rake gitlab:pages:migrate_legacy_storage
```

It requires human intervention on migration and can take a long time
to  complete. (it took about a week on gitlab.com).

We can't remove this rake task because it allows users to control the
process and fix some errors:
* it prints all errors by default, such as invalid symlinks and
projects marked as deployed by absent on pages storage
* it also allows for fix these errors by ignoring invalid symlinks and
marking projects as not deployed
* and it allows users to see the progress/check if everything has been
migrated

However, making every instance admin run this task when upgrading to
`14.0` may create too much work for them.
So we want to run the same migration code as the background
migration.
This way we will migrate the data for most of the users without their
intervention.

It still will be recommended to run the rake task and make sure
everything has been migrated properly.
But in most cases everything should be migrated automatically and even
if users forgot to run the rake task everything should be fine.

* Refactor existing batch migration service to support
calling without threads and just proccessing the batch or projects
* Subsequently refactor rake task due to changed interface
* Shedule a background migration and execute zip migration service
there

Add unique HTML IDs to admin settings forms

See merge request gitlab-org/gitlab!59407

Merge branch '327817-test-failure-spec-features-projects-settings-forked_project_settings_spec-rb-1-2-1-1' into 'master'

Quarantine './spec/features/projects/settings/forked_project_settings_spec.rb[1:2:1:1]'

See merge request gitlab-org/gitlab!59448

Fix flaky pagination test

See merge request gitlab-org/gitlab!59454

Added hover style to emoji picker emojis

See merge request gitlab-org/gitlab!59401

Improve the fork message in the UI

See merge request gitlab-org/gitlab!59036

Resolve "Add missing tooltip to Apply suggestion button"

See merge request gitlab-org/gitlab!59202

Updated datatypes table with CI Pipeline artifacts

See merge request gitlab-org/gitlab!59450

When REMOVING a user, warn Admin user is part of an on-call schedule

See merge request gitlab-org/gitlab!57397

Update to Rails v6.0.3.6

See merge request gitlab-org/gitlab!59328

Enable Style/RedundantParentheses cop for HAML

See merge request gitlab-org/gitlab!58846

Fix flaky pagination test

Do not render Source Editor by default for the repository files

See merge request gitlab-org/gitlab!59430

Remove epic filtered search bar from issue boards

See merge request gitlab-org/gitlab!59336

Remove unneeded stub

See merge request gitlab-org/gitlab!59359

Merge branch '21033-controller-groups-groupmemberscontroller-index-executes-more-than-100-sql-queries-p80-108-3' into 'master'

Resolve group_member policy n+1

See merge request gitlab-org/gitlab!58668

Fix Packages::Debian::FileMetadatum primary key

See merge request gitlab-org/gitlab!59416

https://gitlab.com/gitlab-org/gitlab/-/issues/327817

Tier and version updates for multi project pipelines page

See merge request gitlab-org/gitlab!59389

Allow iteration ids to be passed as a Global ID

See merge request gitlab-org/gitlab!57620

Check maven path for maven file API endpoints [RUN ALL RSPEC] [RUN AS-IF-FOSS]

See merge request gitlab-org/gitlab!59241

Enhance documentation for vulnerability allowlisting

See merge request gitlab-org/gitlab!58909

Update Ruby from 2.5 to 2.7 in Dockerfile templates

See merge request gitlab-org/gitlab!59345

Revert "Merge branch 'move-iteration-as-ee-model' into 'master'"

See merge request gitlab-org/gitlab!59443

Signed-off-by: Takuya Noguchi <takninnovationresearch@gmail.com>

Convert registration groups CSS to utility classes

See merge request gitlab-org/gitlab!58928

Removing hardcoded branch name

See merge request gitlab-org/gitlab!59252

This reverts merge request !59172

Update Gitaly version

See merge request gitlab-org/gitlab!59441

Geo - Release the pipeline artifacts replication and verification

See merge request gitlab-org/gitlab!59323