Add dev release cleanup workflow

[inFocus7]

Currently dev release images and charts are published alongside official releases and do not auto-expire/delete. This will lead to bloat in our repositories over time if we don't manually remove those we created.

In order to circumvent this we should create a cleaner workflow to handle deleting those. It can run either automatically (once a week or month) or be manually dispatched.

For example, because the naming convention of dev releases is dev-$branch-$commit_hash, we could do a weekly (or manual) cleanup run that deletes all images + charts with dev-*. If possible, and even better, we should try to do this for images/charts that were created past a certain date (ex. "delete dev-* images created before the beginning of last week.")