Switch back to Vim

- Change default editor back to vim since doom-emacs is broken at the
  moment
- Conditionally include emacs or vim nix files in configuration.nix
- User username to find dwm-flexipatch path on system
- Add tree and btop to miscellaneous system packages
- Add some cli tools like just and git to home-manager packages
- Add more XDG env vars for config and cache

user/development/default.nix

@@ -1,8 +1,8 @@
-{ config, lib, pkgs, ... }:
+{ config, lib, pkgs, userSettings, ... }:
 
 {
   imports = [
     ./vscode.nix
-    ./doom-emacs.nix
+    ./cli.nix
   ];
 }