Add a license

[soispha]

I would like to package this for NixOS (relevant issue). Unfortunately the lack of a license means that this is to be treated as unfree code, which would make using and redistributing it very hard and cumbersome. I'd would be wonderful, if you could add a Foss license, preferably a FSF approved one like the GPL or LGPL. Of course, if you intended this to be a proprietary application, you can just close the issue.

[Duckonaut]

Oh, I'm gonna license it under BSD-3, same as Hyprland itself. Thought i did already tbh 😅. I don't have access to a PC rn, if you introduce it via PR I can approve it