Add Orbit & FPV camera controls to the player with a UI to select the most appropriate

[nlsdvl]

The default behavior of the player should be to allow navigating the scene with either Orbit or FPV camera controls.
With support for anchoring on Android, FPV controls has been broken.

When a glTF signals MPEG_anchor extension, the camera control becomes problematic:

• it might not be relevant to the content
• it can conflict with the XR Session controlling the camera

Therefore an initial implementation may disable Orbit and FPV camera controls when the scene signals anchoring.