Prioritizing proxy cache improvements

[cyrilcros]

#13627 would allow proxy-cache configuration via webhooks.

• I think with Dockerhub API limitations this would be extremely welcome to get this merged.
• This also removes the need to have a lot of different proxy-cache types for various endpoints, with a lot of issues being reported. See here
• It is one way to deal with the harbor_domain/registry/image URL structure vs the more common registry.harbor_domain/image, which forces you to add ingresses with complicated rewrite rules for each of docker.io quay.io gcr.io...

Could this please get prioritized?