Minor Fixes

[sebjf]

Below is a set of minor fixes that should be made before the start of term.
These are based on observations from last year.
Hopefully we can try and do these next week (they are very minor!)

1. FollowGraspable should have a flag saying whether its grasped
2. It should be easier to delete the Bot from the Local Loopback scene
3. Make sure all events (especially in AvatarManager) are all initialised (not relying on the consumer to do so)
4. RoomClient.Find should be able to be called before NetworkScene.Register, or any other method
5. Turn off Graphic Raycaster on the canvas by default
6. Save and Mirror Project settings should be stored on a per project basis
7. NetworkScene should throw an error when attempting to register an uninitialised NetworkId

[sebjf]

Done (pushed direct as these are all very low risk & impact)