visionOS support

[gabors]

Please add support for compiling on visionOS.

So far the only issue I found to make it work is the usage of the NSUIScreen, as UIScreen is unavalable on visionOS.
This framework uses it to determine the scale

Oh and another spot is
super.accessibilityFrame = containerView.convert(newValue, to: UIScreen.main.coordinateSpace)

Other than that adding #if os(iOS) || os(tvOS) || os(visionOS) does the trick.