refactor: don't include the whole modules

Instead only import the nixos/hm/nixvim module.

This _should_ reduce rebuilds.

example-vm/default.nix

@@ -1,5 +1,5 @@
 {
-  imports = [ ./vm-config.nix ];
+  imports = [ ./vm_config.nix ];
 
   time.timeZone = "Europe/Berlin";
   i18n.defaultLocale = "en_US.UTF-8";

flake-modules/home-modules.nix

@@ -8,7 +8,7 @@
       defaultModules = [
         inputs.nixvim.homeManagerModules.nixvim
         self.nixvimModules.homeManager
-        ../modules/hm
+        ../module/hm
       ];
       nixos = {
         imports = defaultModules;