Integrate with elm-3d-scene

[declension]

Now that elm-3d-scene is near a release, allowing this library to support that in some way seems like a good idea. There is specifically a need for an OBJ importer there among others.

Unclear where this would sit, e.g.

• In that codebase
• This codebase
• A new codebase which pulls both

[declension]

Now deprecating this codebase in favour of https://github.com/w0rm/elm-obj-file