Add support for ComfyUI

[TiagoMarinho]

Adding ComfyUI support to Soph seems to pose some challenges. There's a lack of documentation for its API and it's much more asynchronous in nature than AUTO1111's, responding back immediately with a job ID.

It's unclear how to deal with /metadata, /interrogate and such, and some work will need to be done to be able to retrieve the seed of every image after generation with /dream.