Add normal stencil

[gpetters94]

This adds a Controlnet-1.1 normal BAE stencil, using adapted code from controlnet_aux.

[Abhishek-Varma]

This is cloning the entire repo based on the addition of .gitignore file which I see.

Please look at a smaller delta to enable to normal just like rest of the features.
I believe openpose, as of now, was quite involved and the minimal inclusion of it is still sustainable.

I'll try to get some cycles and see if I can give you pointers - but there is a Git repo from which you can get a very minimal repo, under the context that normal feature is supported by the original implementers of ControlNet.