Add 3D model Elasticsearch model

[AetherUnbound]

Description

We will need to add a 3D model model (model²?) to our list of Elasticsearch syncable models in elasticsearch_models.py. This commit may prove as a useful reference: WordPress/openverse-api@cf21b73

The ES models represent the fields that we will want to search against. This may not be all of the fields available for the media type, we'll need to check against images & audio to see what feels we should include/exclude.

Alternatives

Additional context

Implementation

• 🙋 I would be interested in implementing this feature.

[sarayourfriend]

Closing as 3d models are indefinitely on hold and no work should be done on them until we re-plan this project.