DownloadManager Git LFS support
Hey ! Actually it works, just pass the right URL ;)
The URL must be the one with “/resolve/”

e.g. https://huggingface.co/datasets/imagenet-1k/resolve/main/data/test_images.tar.gz

You can even pass a relative path to the dl_manager instead, like `dl_manager.download("data/test_images.tar.gz")` Amazing it works, thanks!
### Feature request

Maybe I'm mistaken but the `DownloadManager` does not support extracting git lfs files out of the box right?
Using `dl_manager.download()` or `dl_manager.download_and_extract()` still returns lfs files afaict. 

Is there a good way to write a dataset loading script for a repo with lfs files?

### Motivation

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### Your contribution

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