Hide NavBar Android

It could be nice to have the navbar of Android hidden.
UMG doesn’t scale based on it too, which is a bug I think.

This is coming soon. There is experimental support in 4.8 preview, but not exposed at the moment. In, change this line:

private boolean ShouldHideUI = false;

to true. This turns on immersive sticky on KitKat and above. Eventually this will have a checkbox and runtime controls.