specializations: Configure inside default.nix

This makes it possible to define specializations that are technically
modules without having them placed in the modules directory. This is
mainly useful to separate core Hyprland logic from desktop environment
logic.

specializations/default.nix

@@ -1,6 +1,11 @@
 {
-  imports = [
+  specialisation = {
+    gnome.configuration.imports = [
       ./gnome.nix
+    ];
+
+    plasma.configuration.imports = [
       ./plasma.nix
     ];
+  };
 }

specializations/gnome.nix

@@ -1,7 +0,0 @@
-{
-  specialisation.gnome.configuration = {
-    imports = [
-      ../modules/gnome.nix
-    ];
-  };
-}

specializations/plasma.nix

@@ -1,7 +0,0 @@
-{
-  specialisation.plasma.configuration = {
-    imports = [
-      ../modules/plasma.nix
-    ];
-  };
-}