use docker for default install

Currently default plugin installation is only implemented for pip and poetry, which is suboptimal.

Figuring this out for compiled languages would be pretty hard because you need to figure out how to detect / install each toolchain, which is why I propose using docker or podman (daemonless docker) for building the plugin into a container which cln can then run through a small generated script. Each language could have a default image or provide a custom one in `coffee.yaml`.

If docker / podman isn't installed on the machine we could still fallback to the current way of doing things.

I'd be willing to try implement this.