Support for self-rotation inside Manipulator on mobile

[wes-nz]

Feature Request

Manipulator.cpp doesn't appear to allow self rotation in Orbit Mode.

This gesture is specific to mobile platforms, in Orbit Mode it should rotate the camera on itself, see below.

https://user-images.githubusercontent.com/2945380/145916602-1f44c27a-554a-4ec8-90c5-03158d31eb3d.mov

Describe the solution you'd like: Update Manipulator.cpp to include a new method allowing self rotation. Even better, also updating GestureDetector.kt to detect the rotation gesture out of the box.

Describe alternatives you've considered: Detecting the rotation with a custom GestureDetector and rotating the camera, however the rotation get overwritten by any manipulator using the camera.

OS and backend: Android