Add support for the revolutionary B-Lora - Content and Style Separation

https://b-lora.github.io/B-LoRA/

I think B-LoRA is an extremely interesting concept, its not just a new way out of a thousand ways to train any kind of lora...

Nope, it's specifically a LoRA that targets only blocks OUT0 and OUT1 of the UNet of SDXL, and from very brief training AND A SINGLE IMAGE, it learns a decoupled representation of "style x content" of the image...
that means we are able to make absurdly tiny loras out of single images, for then applying that content of the image IN OTHER styles.
I don't get why the community hasn't already got a whiff of this.

If this gets well spread and used, it means that users of pony and users of sdxl in general won't need massive loras of many x ranks that applies to every single block of UNet in order to get the character (content) or style they want.