Upstream production ready docker image

I see that you currently don't offer a docker image ready for production, and I'd like to come and help maintain that.

Would you be willing to accept such a contribution? Do you have a runner/registry on this repo?

If yes for both, then' I'll PR the work I found there: https://gitlab.utc.fr/picasoft/projets/dockerfiles/-/tree/master/pica-castopod

It could also be in a different repo, so then we have different CI and you could give me "higher" rights on the other repo.

I always consider we should collaborate upstream, and I hope you'll accept it!