This is now merged in! 
I also implemented the ability consume settings in theme JavaScript like so: https://github.com/discourse/discourse-linkify-words/blob/master/common/head_tag.html#L3 (must be a type="test/discourse-plugin")
@Osama I feel we do need a few refinements if you feel up to it:
Not a huge fan of having this in the UI, I am fine for all the config to happen in the remote git repo. This is very much a feature for ninja theme creators and not the general public.
We don’t need this, cause we already have a theme section:
Lastly, we need a fancy howto here explaining how to use it and to update:
If you can give it a shot 