Add zero-shot obj detection notebook to docs
Adds OWL-ViT demo notebook links to the official notebooks docs.

I'm currently working on adding TF support for this model and we'll be promoting it soon.
_The documentation is not available anymore as the PR was closed or merged._<|||||>> Thanks for adding! Although I think we need to split up that long list of notebooks by modality/task.

I agree! I will add another PR to organize the notebooks page.