Support `fsspec` in `Dataset.to_<format>` methods
Hi @mariosasko unless someone's already working on it, I guess I can tackle it! Hi! Sure, feel free to tackle this. #self-assign I'm assuming this should just cover `to_csv`, `to_parquet`, and `to_json`, right? As `to_list` and `to_dict` just return Python objects, `to_pandas` returns a `pandas.DataFrame` and `to_sql` just inserts into a SQL DB, is that right? Fixed by #6096. 
Supporting this should be fairly easy.

Requested on the forum [here](https://discuss.huggingface.co/t/how-can-i-convert-a-loaded-dataset-in-to-a-parquet-file-and-save-it-to-the-s3/48353).