📦 Created config files with common code

- Created common.nix for various configs
- Created theme.nix for theme related configs
- Moved some code to more logical files
- Moved some standalone files into nix multiline strings, in order to
  inject data

modules/nix-helper.nix

@@ -1,9 +1,7 @@
-# Nix-Helper: swgithub.com/viperML/nh
-{ ... }:
-
+# Nix-Helper: github.com/viperML/nh
 {
   programs.nh = {
     enable = true;
-    flake = ./.;
+    flake = ../.;
   };
 }