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/.config/nvim/templates/boilerplate.c

@@ -0,0 +1,6 @@
+#include <stdio.h>
+
+int main() {
+  printf("Hello, world!");
+  return 0;
+}