quartz: implement maximized/unmaximized

quartz: implement maximized/unmaximized

Instead of using the default zoom behaviour use the internal
maximized state for selecting our own zoom target. This makes
zooming work for CSD windows where for some reason the
given default zoom target is the current window frame itself
resulting in a shadowless window of the same size.

While this makes the zoom button behave a bit different as expected
it makes things more consistent with other platforms and fixes CSD
zooming.