idea is to have a directory `websites/` which contains all our static
sites, with the name of each subdirectory also being their domain. Then
Nix can just read that directory during build-time and automatically
generate nginx virtualHosts for all of them (note that the
subdirectories have to contain a `default.nix` specifying how to build
the site for that to work).
Thus we could avoid the dependency on gitlab pages.
