[FEAT] For theming allow setting the config directory via enviromnet variables

### Description If I change to a different theme in my Hyprland, this Lua line will be run. hl.env("KITTY_CONFIG_DIRECTORY", "/home/johnny/.config/hypr/themes/AstroDark/kitty") This is for kitty chance, it where it looks for kitty.conf. This way it can be transparent on theme A but not on theme B. I would love to see a similar feature for Fastfetch. I could do the same thing with an alias, combining it with the --config flag, but this is better in my mind. ### Motivation I have build my own theme switcher in Hyprland and i would like to direct the directory Fastfetch looks in by setting an environment variable so i can have per theme different looks for fast fetch. ### Additional context _No response_