Add cache cleanup option to local cache exporter

[MarcelCoding]

Implemented an option to remove old versions of a newly created image and images older than a specified time.

Reason/Usecase: https://github.com/docker/build-push-action/issues/252 My temporarily solution: https://github.com/docker/build-push-action/issues/252#issuecomment-744400434

[tonistiigi]

BuildKit doesn't have an image store. For cleaning up build cache there is buildctl prune (docker buildx prune)

[crazy-max]

@tonistiigi It's about the local cache exporter. Atm caches are copied over the existing cache so it keeps growing (#1850).

[CMonoceros]

Is there any progress on this option?

[Niek]

https://github.com/docker/buildx/pull/535 has been merged now, I think https://github.com/moby/buildkit/pull/1974 is still WIP.

[lexfrei]

Any news?

[demartis]

It's been over 2 years, is there any news about this issue?

[rreckonerr]

[acidobinario]

LGTM 👍 💯