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/snippets/rust-mode/for-loop

@@ -0,0 +1,7 @@
+# -*- mode: snippet -*-
+# name: for-loop
+# key: for
+# --
+for $1 in $2 {
+    $3
+}