Wishlist: add Matcha Dark Sea as a preset

[ameris1]

I LOVE this theme. Wish that I could have a way to tweak it in a way which I don't head into a textpad to edit the colors.

[actionless]

PRs are welcome

[actionless]

also please check the step-by-step guide on how to add a theme: https://github.com/themix-project/themix-gui/wiki/How-to-contribute-your-theme-from-Github-website