DOC gradio integration

[merveenoyan]

This PR includes documentation for gradio integration.
I added it to plot_hf_hub.py given it's hub related. However, for some reason it can't see there's an example data.

ValueError: No example data found in README.md of skops-ci/hf_hub_example-96069c5a-d82d-4ffd-b1b8-5ac554c7f7ce - Cannot build gradio demo. See the README.md here: https://huggingface.co/scikit-learn/tabular-playground/blob/main/README.md for a reference on how to provide example data to your model.

Also I see in the example there is example input. (the latest model I pushed and the one I got the above error from)
(I also tried on my local, it can build the interface on this Space with model pushed through this tutorial, see
the model and the space)

pinging @freddyaboulton

[adrinjalali]

Thanks @merveenoyan

[merveenoyan]

@adrinjalali it looks like below:

also now that we don't have it in examples, I removed it from min dependencies.

[merveenoyan]

@adrinjalali mypy is complaining again 😂

[merveenoyan]

@adrinjalali can you review? can't ask for a re-review

[adrinjalali]

otherwise LGTM.

[BenjaminBossan]

I have a few more comments, the rest looks good to me.