Resurrect old oxygen theme (we don't want to loose it) and create .desktop file for new one

So now we have 3 themes, yay!

Oxygen is still used as a default one, this can be adjusted - what do our artists think? :)

Eugene, I named it kmines_green, and put simple and dumb descriptions in green.desktop, I think you'll want to adjust them :). As well as svg filename - feel free to rename it

And thanks for great theme! (although my notes I sent you still stand ;))