buildClan function: export all machines via nixosModules/darwinModules

We want each machine not only to be exposed via nixosConfigurations but also as a module.
This allows re-importing the machine in tests and override the architecture for example.

lib/build-clan/machineModules/forName.nix

@@ -26,7 +26,4 @@
       inherit name;
     };
   };
-
-  # TODO: move into nixosModules
-  networking.hostName = lib.mkDefault name;
 }