[REQ] Support pushing to registry directly

[RealHarshThakur]

What kind of request is this?

Improvement of existing experience

What is your request or suggestion?

It would be nice to push to the image registry directly. Like :

copa patch -i docker.io/library/alpine:3.16.4 -r patch.json -p ttl.sh/alpinepatched:1h

One side-effect of this would be that copa wouldn't rely on Docker anymore if there is a remote buildkit setup as I mentioned here. https://github.com/project-copacetic/copacetic/issues/285#issuecomment-1708239927