Massive configuration overhaul

Currently paying the price of months of non-diligent git usage.

Here's what has changed.

- Theming support in Gvcci and wpgtk
- Dropping support for i3
- Supporting EXWM
- Many Elisp modules
- Collapsed redundant directories in ./configs

configs/shared/emacs/.emacs.d/snippets/nix-mode/shell-nix

@@ -1,12 +0,0 @@
-# -*- mode: snippet -*-
-# name: shell.nix boilerplate
-# key: import
-# --
-with import <nixpkgs> {};
-
-stdenv.mkDerivation {
-  name = "$1";
-  buildInputs = [
-    $2
-  ];
-}