Add palettes

[KingNook]

Context

I would quite like to have the option to easily switch out color schemes. The easiest way I can think to do this is to have separate palette files that the colors file will sort out

Thoughts / Challenges

Probably a config style file (looks like I'll be going with .yaml files on this) and a separate config file to define the palette in use (although it may also be worth later down the line having a way to change palette during runtime).

I will also have to replace the color references (eg instead of IVORY and AFW, I would need to have BACKGROUND and COLOR_2 or something along those lines and change this in the other files as well.