Separate System and User packages

- Move user programs out of systems section and int
  user section
- Install user packages with home manager rather than
  system wide

user/terminal/kitty.nix

@@ -0,0 +1,7 @@
+{ config, lib, pkgs, ... }:
+
+{
+  home.packages = (with pkgs; [
+    kitty
+  ]);
+}