v0.4 - Avatar hands support!

Improvements:
#4 - Added support for Avatar Hands.
Avatar hands are now enabled by default.
They can be toggled on and off via the new MRTK-OculusConfig scriptable object in the ThirdParty resources folder.
Avatar hands have fully mapped hand joints, which bring full support for hand-based interactions using them.
Changed to make use of grip button for near grabbing, as finger tip is used for selection interaction on near interactibles.
Updated sample scene to fully support everything the HL2 interaction scene supports.

Fixes:
#3 - Fixed hand bounds not being updated for controllers. This was due to not calling the hand joint input system update event.