Rename hunyaun to hunyuan_video

BUR #656 is pending approval.

rename hunyuan -> hunyuan_video

Rename hunyuan to hunyuan_video to differentiate from potential Hunyuan Image 2 uploads

@ellipse9515 Please write a wiki for hunyuan first. I'd vote no if they are the same family of models. And the former tag only has 7 posts.