[Feature] Adopt FluxPipeline to support a Flux models

There is a new promising model. https://huggingface.co/docs/diffusers/main/en/api/pipelines/flux

It would be good to take this model pipeline from diffusers package and add a canvas and attention / transformer additions from StableDiffusionXLOmostPipeline if possible.

Also, please take a note that there is a reduced T5 model available to save some VRAM https://huggingface.co/comfyanonymous/flux_text_encoders/tree/main