Supervisor UI on non-VR screen

[sauterl]

During the last demo, we realised that a master or supervisor UI on the non-VR screen would be very beneficial. The UI panel would include helpful infos sucha as:

• Checkbox per controller to de-/activate it
• Means to configure and restart the timer
• Ability to set the player's position (i.e. respawn to room k )

[Spiess]

I've started working on the UI in the branch supervisor-ui (58e853c). I've taken care of the UI elements and their behaviour, but because I don't have access to a VR headset for testing, I wasn't able to connect it to the existing logic.

All that remains for the first two subtasks is to call functions from and complete the TODOs in Assets/Scripts/Unibas/DBIS/VREP/UI/SupervisorUIController.cs.

[sauterl]

I will have a look at your TODOs in the following weeks.
There is some preparation for the third subtask on the respawn-and-settings branch (4d4edec)