[modules] fix microvm.host 'leak'

including the malobeo module caused microvm to include microvm.host
which caused super annoying trouble and 2 days of debugging because
microvm.host.enable defaults to true...

outputs.nix

@@ -112,11 +112,14 @@ in (utils.lib.eachSystem (builtins.filter filter_system utils.lib.defaultSystems
       self = self;
     });
 
-    nixosModules.malobeo.imports = [
-      ./machines/durruti/host_config.nix
-      ./machines/modules/malobeo/microvm_host.nix
-      ./machines/modules/malobeo/wireguard.nix
-    ];
+    nixosModules.malobeo = {
+      imports = [
+        ./machines/durruti/host_config.nix
+      ];
+
+      microvm.imports = [ ./machines/modules/malobeo/microvm_host.nix ];
+      vpn.imports = [ ./machines/modules/malobeo/wireguard.nix ];
+    };
 
     hydraJobs = nixpkgs.lib.mapAttrs (_: nixpkgs.lib.hydraJob) (
       let