ComfyUI Node: Region Mask

Implement Region Attention for Flux model. Add node RegionAttention that takes a regions - mask + condition, mask could be set from comfyui masks or bbox in FluxRegionBBOX node. This code is not optimized and has a memory leak. If you caught a OOM just try run a query againg - works on my RTX3080. For generation it uses a usual prompt that have influence to all picture and a regions that have their own prompts. Base prompt good for setup background and style of image. This is train-free technique and results not always stable - sometimes need to try several seeds or change prompt.