Enable snapshot_download for different repo types

[nateraw]

Is your feature request related to a problem? Please describe.

Currently, snapshot_download only works for model repos. It would be nice to add repo_type kwarg here and pass it along to the underlying functions to enable snapshot downloads of dataset repos.

Describe the solution you'd like

from huggingface_hub import snapshot_download

cached_repo_path = snapshot_download('nateraw/huggingpics-data-2', repo_type='dataset')

Describe alternatives you've considered

You can do this via Repository, but its more verbose. Also, a generic download_file_or_path function may be nice too...(Related to #460 )

from huggingface_hub import download_file

path = download_file('nateraw/huggingpics-data-2', 'images/')

Additional context

I was playing around with upload_to_hub and load_from_hub functions for Hugging Pics' datasets when I ran into this. Just wanted to grab the entire repo and load images from there, but realized its not possible with snapshot_download.

[osanseviero]

I think your solution is fine and would be consistent with the other methods.

cc @LysandreJik @muellerzr

[LysandreJik]

Indeed, that would be a nice addition!

[Wauplin]

repo_type kwarg added in #801.