CameraControls rework (Input/Controller overhaul)

[kpal81xd]

Overview

This PR aims to split the camera controls down into two core components:

• Input Sources which represent a collection of deltas generated from one or more input devices. These can range from a mouse movement delta to a gamepad joystick delta.
• Input Controllers which represent the constrained transformations that are to be performed e.g. orbiting around a particular focus point or camera flying (unconstrained) .

Together the deltas from an Input can be collected into a "frame" of deltas which are then applied to the specified controller to perform the required action.

Input Sources

SingleGestureSource - Single touch or virtual joystick input
DualGestureSource - Split screen touch or virtual joystick input
MultiTouchSource - Multi touch input (includes pinch handling)
KeyboardMouseSource - Keyboard and mouse input
GamepadSource - Game pad input

Input Controllers

FlyController - Applies free-fly mechanics to a base transform
OrbitController - Applies orbiting mechanics to a base transform

Design Doc

https://docs.google.com/document/d/1r2ywuzxbte6DwlEJzWgyD-fTDNyp-7P0PKLFefrgV9Y/edit?usp=sharing