Add VR hand interaction with ImGui holographic menus

[xthexder]

The current idea is to have a 2-layer menu to allow more points of haptic feedback, and better precision with button actuation.
The XY position of the virtual cursor should be locked once the player's finger passes through the top layer, and then click action would happen on the second layer.
Some experimenting would need to be done to determine a way to input a click + drag, but this could possible be avoided in the menu design.