Allow pulling container images using personal access tokens

Are there points in the code the reviewer needs to double check?

This touches both authentication and authorization, so please double check the security side of it all.

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• API support added
  • Check if this needs additional changes to support
• Tests
  • Added for this feature/bug
  • All builds are passing

What are the relevant issue numbers?

Fixes gitlab-org/gitlab-ce#19219