[Enhancement]Remove background will improve openpose、dwpose and segment

[sdbds]

Fannovel16/comfyui_controlnet_aux#94 (comment)

for Fannovel16 noticing
i found remove background can make animefacesegment preprocesser more accurate.

i tested with openpose and dwpose, it works well too
so maybe we can choose some remove background model for these preprocesser

anime can use https://github.com/SkyTNT/anime-segmentation

real photo has too many models.

any suggestion about real photo remove background model ？

Condition	openpose	dwpose