`dev-notes` are severely outdated. I dropped everything except one note
that I moved to hacking.md. The parts about creating users are also
covered elsewhere.
The `update-dbix` part got a just command to make it discoverable again.
* justfile, inspired from Lix.
* let foreman use the stuff from outputs, similar to what Lix does>
* mess around with PERL5LIB[1] and PATH to get tests running locally.
[1] I don't really know how `Setup` was found before tbh.