refactor: retire the aquamarine VM host

Aquamarine's services now run directly on kubevirt-youko, so the guest
definition is no longer needed:

- move its service modules to hosts/k8s/kubevirt-youko/aquamarine/ and
  drop the explicit import list, leaving aquamarine-services.nix with
  just its IP and secret groups
- delete the guest base, journald override, output entry and home config
- repoint the eval tests that read the guest's config to kubevirt-youko
- drop the now-dead 'aqua' colmena recipe and its image upload

The aqua KubeVirt VM itself is deleted separately; the name is kept in
the docs for a possible later test microvm/qemu-vm on idols-ai.

Justfile

@@ -230,15 +230,9 @@ youko mode="switch":
 upload-idols verbosity="normal":
   #!/usr/bin/env nu
   use {{utils_nu}} *; 
-  upload-vm aquamarine 80Gi {{verbosity}}
   upload-vm ruby 100Gi {{verbosity}}
   upload-vm kana 100Gi {{verbosity}}
 
-[linux]
-[group('homelab')]
-aqua mode="switch":
-  colmena apply {{mode}} --on '@aqua' --verbose --show-trace
-
 [linux]
 [group('homelab')]
 ruby mode="switch":