RFC: Adding support for image (and later audio/video) generation models

[cwang]

Is your change proposal related to a problem? Please describe.

Multi-modal is the likely future. Before single multi-modal models mature for real use, we should consider adding support for image generation models which have seen their use in particular sectors.

What Docq could offer in this case is the synergy between text and image generations, from the same set of private docs.

Propose the solution you'd like

Probably built on top model selections, see #12

Describe alternatives you've considered

Consider supporting open source self-hosted image models as the natural next step.

Additional context

As mentioned, single multi-modal models could appear on the horizon soon; they could be easily supported in the current codebase. This RFC is about having different models for specific use cases (text & image generations).