As an admin/user I can maintain a controlled registry that doesn't continually grow in space

Is your feature request related to a problem? Please describe.
While for synced repos there is an option to sync content in a mirrored mode( not just additive), and then trigger orphan cleanup(still half solution). For pushed repos the content always gets accumulated.

Describe the solution you'd like
Introduce a concept of image garbage collection. Garbage collection will ensure efficient use of resources for active objects by removing objects that occupy sizeable amounts of disk space

Describe alternatives you've considered

1. set retain_repo_versions to 1 on the push repo
2. manually remove undesired images by digest. It will delete its tags and blobs(in case they are not referenced in other images)
3. Trigger orphan cleanup. Might need to adjust orphan_protection_time based on needs.

For synced repos one can also consider and combine the disk reclamation feature in case repo versioning is needed.

Additional context
Design and criteria of garbage collection - TBD
Disclaimer - this feature might be incompatible with repo versions, and might require, or will take into account to garbage collect only those repos that do not have versioning enabled aka repo_version_retention=1

No files, tests, or entry points are named. Start by reviewing the existing mirrored sync, orphan cleanup, pushed-repository version retention, and digest deletion behavior described in the issue. Done requires agreed garbage-collection design and criteria that address disk reclamation, repository versioning, retention, and orphan protection.