Draft: PDM to migrate queued and future Sidekiq jobs

MR merged together with !142577 (merged) for easier merge coordination.

What does this MR do and why?

Part of gitlab-com/gl-infra/scalability#2720 (closed)

Migrate jobs that don't belong to any queue from the routing rules to their correct queue.

Why is the migration needed?

• Before %16.0, jobs are pushed to their worker-named queue by default, equivalent to [['*', null]] in routing rules terms.
• On %16.0, routing rules are defaulted to [['*', 'default']] which means all jobs from all worker class are pushed to the default queue. However, Sidekiq server still listens to all queues by default (ie sidekiq['queue_groups'] = ['*']).
• In !142577 (merged) %16.9, we're changing queue_groups to be default,mailers if routing rules aren't set.
• Scheduled and retried jobs might still be left in their worker queues. For example, scheduled/retried jobs while in pre-16.0 could be scheduled in the distant future, and these will remain in their individual queues. This migration ensures no jobs will be lost while upgrading to %16.9

Note:

1. The code is mostly copy-pasted from https://gitlab.com/gitlab-org/gitlab/-/blob/7066e106511295f69e380eef89c7e9a805a29330/lib/gitlab/sidekiq_migrate_jobs.rb which is a Rake task designed to migrate the jobs whenever routing rules are updated.
2. We have tried to introduce the PDM before, but was reverted/cancelled because different approach was taken back then: a. Queued jobs: !100392 (merged) b. Future jobs: !103001 (closed)

‼ This MR has to be in the same release as Expand sidekiq queue_groups to default (!142577 - merged) so that the PDM takes care of jobs in the orphaned queue.

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