Theme config

The scripts and config files for the theme must be in a directory sym-linked to ~/.config/leftwm/themes/current/.

theme.ron: LeftWM theme config including border color, margins, etc.
up: This script is called on login. The theme.ron must be loaded by this script using LeftWM's LoadTheme command:

leftwm command "LoadTheme ~/.config/leftwm/themes/current/theme.ron"

Add lines to load other theme elements like eww daemon, polybar, or anything you have configured for your desktop.

down: To unload the theme. Not sure why this is required. I might modify thislater if required.