Since the delivery of mumble.hacc.space/murmur.hacc.space via gitlab pages
broke (for whatever reason), I've packaged the site into an ad-hoc nix
derivation, which is now delivered locally by nginx instead. This has a
couple benefits (mainly that we no longer depend on gitlab pages), but
also the downside that we can't just update the site via gitlab's CI/CD
pipelines anymore.
