Add an example to demonstrate RHI rendering in the scenegraph with a
custom QSGRenderNode. Works for Vulkan/OpenGL/Metal/D3D rendering
directly, and into a layer.
Change-Id: I0333f63fd729312b71e51f5b6376e46f8afe1fe6
Reviewed-by: Laszlo Agocs <laszlo.agocs@qt.io>