Add (vague) V-Objective option

[chavinlo]

There are some things I think could be done better (I will if I have time)

• Load V-Prediction automatically from the model if noise_scheduler.config.prediction_type is v_prediction

the problem with this is that during inference it gets ignored for some reason and goes directly with the normal (non vobjective) DDIMScheduler. idk if it comes from the config check, so I'm just forcing it here

• Let the user chosse more schedulers?

currently there are two schedulers that support velocity: ddpm and ddim at least on the diffusers repo

• Check if Diffusers version is above v0.9.0 (latest)

the v objective was added 6h ago, and last release was 3 days ago

[chavinlo]

Do not add yet. Testing it right now and it seems the loss is over the sky

[chavinlo]

Closed as this has been added