Add kicad-git v0.1

This is simple plugin which does two things:

• saves current board
• opens https://git-scm.com/docs/git-citool for creating commits

This saves some clicks. I was not aware that native git support is added for KiCad 8.0 (kicad/code/kicad#10441 (closed)) when I started this plugin. Not sure how useful this might be, but since it works for KiCad 7.0 I think it is worthwhile to include it here.