In https://gitlab.com/gitlab-org/gitlab/-/merge_requests/40717 and
https://gitlab.com/gitlab-org/gitlab/-/merge_requests/42128, we
propagate instance-level integrations to groups.

This propagates group-level integrations to the lower levels using the
same approach of batching and Sidekiq queues.

This is the backend behavior when saving an instance-level or
group-level integration:
- Update inherited integrations (find all integrations inheriting from
  the instance-level or group-level integration that we are updating).
- For instance-level:
  - Create integration for all projects without integration
  - Create integration for all groups without integration
- For group-level:
  - Create integration for projects belonging to the group without
    integration (new).
  - Create integration for groups belonging to the group without
    integration (new).