Create a first-pass draft of IIIF Presentation API specifications supporting 3D

[JulieWinchester]

This work will involve taking what has been learned so far in TSG meeting conversations and experimental prototyping and using it to put together an early initial "first-pass" draft of a IIIF Presentation API specific that would support 3D in at least some of the ways described in the core user story issues in this issue tracker.

[JulieWinchester]

Pre-Alpha 4.0.0 Presentation API documentation example: https://preview.iiif.io/api/rob_3d/presentation/4.0/