DOC: Add Hugging Face Hub access
Hi team ! We recently made most of the 200k+ datasets from the community on Hugging Face loadable in pandas :)
And we even show the code snippet to load a dataset on each dataset page (see images below)

In this PR I added documentation on accessing Hugging Face Datasets using `fsspec`. It uses `hf://` paths and the implementation is part of the `huggingface-hub` library. Let me know what you think !


1. "Use this dataset" button on a dataset page:
<img width="1290" alt="image" src="https://github.com/user-attachments/assets/6ab57ddf-c42d-4892-8572-6bd0e772e7ce" />

2. Modal showing [pandas code snippet](https://huggingface.co/datasets/google/FACTS-grounding-public?library=pandas):
<img width="1294" alt="image" src="https://github.com/user-attachments/assets/c08ca12f-3b98-4748-8569-8d71892234c3" />

closes https://github.com/pandas-dev/pandas/issues/46000

Added a section in ecosystem.md :) And I removed the pip extra, but I think the HF fsspec implementation should be an option at the same level as S3 or GCS no ?

I kept HF as an option in the docs on fsspec support in `io.rst` as well, let me know if it's fine. Thanks @lhoestq 