[#42] add controller support, adjust sensitivity

The camera can now be controlled via gamepad!

PilotCameraController:
- rotation via right joystick (horizontal, vertical)
- zooming via left and right trigger
- translation in xz plane via left joystick (horizontal, vertical)
- translation in y direction via left and right bumper

TrackballCameraController:
- orbiting via right joystick (horizontal, vertical)
- change radius via left joystick (vertical)