[REQ] Support for Copa to connect to remote buildkit

[RealHarshThakur]

Really cool project :)

What kind of request is this?

Improvement of existing experience

What is your request or suggestion?

Hey folks, I'd like to use Copa using a remote buildkit daemon, if people have builds and patching done over the same buildkit instance, they'll benefit from the cache.

I've submitted a PR to support it: #284

[RealHarshThakur]

On a separate note, I also realised that even with remote buildkit in place, this will still require docker daemon to run due to this bit here.

I wonder if we can instead have a "push to registry" step there optionally. I'm happy to create a different issue and a PR to support it too, wanted to check if you folks have any opinions around it.