[Request] Add Button vertical padding option

[yn4v4s]

It would be nice to have the option to adjust the button vertical padding, because when button size is less than 5px, the buttons does not align well.

[ishovkun]

I knew that was coming :-)

[MarianArlt]

This would be a nice addition. I personally very deeply dislike the tiny vertical size of the breeze window title decoration in general. Have avoided it ever since only because of this fact. Great work!