Improve Documentation

Lots of little jobs here:

• Break the nightmare fuel config table out into its own doc file, and provide .env.example
• Provide guide on running for various uses
• Example docker-compose.yml

Should also consider a doc site, which I think we can deploy with tangled CI?

There’s also nix packaging work going on elsewhere which I’d like to provide examples for if poss. idk if that should be kept here tho