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.d/wpc/string.nix

@@ -0,0 +1,8 @@
+{ pkgs ? import (builtins.fetchTarball
+  "https://github.com/tazjin/depot/archive/master.tar.gz") {} }:
+
+pkgs.writeElispBin {
+  name = "string";
+  deps = epkgs: [ epkgs.dash epkgs.s ./prelude.nix ];
+  src = ./string.el;
+}