Firefox extension

Hi, i was going to post this on reddit but i saw that its inactive for [a good reason](https://old.reddit.com/r/catppuccin/comments/143fb5y/the_catppuccin_subreddit_will_be_shutting_down/). If this is not the correct place feel free to close it immediately.

> Im ricing my linux setup, and i want firefox to follow my current Catppuccin theme. The problem is that i also have a switcher between light and dark mode, or sometimes i want to change the highlight color. The [firefox colors version](https://github.com/catppuccin/firefox) doesnt allow this, so i wrote this extension. You could install it from the [Firefox addons page](https://addons.mozilla.org/en-US/firefox/addon/catppuccin-selector/)


Start with the linked Catppuccin Selector extension and Firefox Add-ons page, then compare their stated behavior with this repository. The issue names no file, test, requested repository change, or acceptance criteria, so the scope and definition of done would need to be established first.

Written by the indexing model from the issue text.