Drop the now-meaningless kubevirt- prefix and move the hosts out of
hosts/k8s/, following the existing 12kingdoms-shoukei layout: the
directory and output carry the theme prefix while the configuration,
hostname and colmena target are the bare name (shoryu, shushou, youko).
- hosts/k8s/kubevirt-* -> hosts/12kingdoms-*; the shared disko config
becomes host-disko-fs.nix; the now-different relative imports are fixed
- outputs, vars/networking.nix keys, the Justfile recipes/tags, the eval
tests and the docs follow
- colmena reaches these hosts by IP (a new targetHost override), since
their DNS name changes with the hostname and is not resolvable until
the router learns it
Ryan Yin