fixed camera Keybindings + Third Person Camera Mouse control

[markusobi]

• added mouse control for Third Person Camera (x/y-axis + mousewheel zoom)
• Moved the registering of the bindings out of the PlayerController.
• Camera Hotkeys F1-F4 should work again now

[tomedi]

Camera moving by mouse works great. Do you think you can implement left click for interactions as well?

[markusobi]

There is still some issue after world-switch. I need to unbind the Camera bindings in the destructor of the CameraController.