Add viewer for 3D models and scenes

Useful for things like
- showing the current vehicle attitude
- this could use the vehicle's active model when using BlueOS, and could likely make use of @Williangalvani's model viewing code from the BlueOS [Vehicle Setup](https://blueos.cloud/docs/blueos/1.1/advanced-usage/#vehicle-setup) page
- SpaceX have recently added this kind of functionality to their streams:

- showing the vehicle/mission within its 3D environment
- this is particularly useful if there's no camera feed, but there is a positioning system and a map with buildings and/or terrain data
- this [was recently demoed in QGC](https://www.youtube.com/watch?v=aJI5349crG8), using OpenStreetMap data
- should support custom 3D area models as the source
- should support projection mapping from an overhead / satellite image
- even better if it also supports overlay / live projection/photogrammetry from a camera feed on the vehicle
- could (ideally) support live updates from a source of surface distance data compared to the vehicle's barometric altitude/depth
- for water-based use-cases this would need to take tide level (and waves?) into account

If done using `.glb` files this could likely integrate quite nicely with AR/VR viewers/headsets.

The issue names no files, tests, or entry points to start from. First clarify the smallest supported viewer scope and locate the relevant viewer or widget entry point; done would require an agreed implementation and validation plan for that scope.

Written by the indexing model from the issue text.