hostName must be dnsLabel and therefore cannot be machineName

[blaggacao]

https://github.com/DBCDK/morph/blob/c048d6339f18613a1544bc62ff852cb4c6de1042/data/eval-machines.nix#L35

https://search.nixos.org/options?show=networking.hostName&query=networking.hostName&from=0&size=30&sort=relevance&channel=unstable#disabled

Out of hostname.example.com it should be only the dns label hostname.

It also means the examples are not tested: https://github.com/DBCDK/morph/blob/c048d6339f18613a1544bc62ff852cb4c6de1042/examples/simple.nix#L17

[blaggacao]

It would also be good to arrange by default for hostname --fqdn to return the FQDN for identity discovery in the absence of a DNS or DHCP (static network yay! wireguard hurray!):

See:

• https://github.com/NixOS/nixpkgs-channels/commit/234d95a6fc75208266049fa2f57641d6f4e5bd2a
• https://search.nixos.org/options?show=networking.domain&query=networking.domain&from=0&size=30&sort=relevance&channel=unstable#disabled