video dataset loader/parser
Hi! We've just started discussing the video support in `datasets` (decoding backends, video feature type, etc.), so I believe we should have something tangible by the end of this year.

Also, if you have additional video features in mind that you would like to see, feel free to let us know Coool thanks @mariosasko  Hey @mariosasko, I was wondering if there's a way to load video data currently in the library? 
Alternatively is there a way I could hack it through the dataset.from_dict() method? I tried to hack it, but the issue I run into is that earlier I was doing a `cast_column()` call for the `Image` feature, but now I'm not sure about to do if I want the dataset to have the following keys when I call from_dict on it:
`{"caption":[list of text captions], "video_frames": [list of image lists with one image list corresponding to one video]}`

Maybe something like `cast_column("video_frames", List(Image))` ..
(This is assuming I have already extracted frames from video)
you know how you can [use `load_dataset` with any arbitrary csv file](https://huggingface.co/docs/datasets/loading#csv)? and you can also [use it to load a local image dataset](https://huggingface.co/docs/datasets/image_load#local-files)?

could you please add functionality to load a video dataset? it would be really cool if i could point it to a bunch of video files and use pytorch to start looping through batches of videos. like if my batch size is 16, each sample in the batch is a frame from a video. i'm competing in the [minerl challenge](https://www.aicrowd.com/challenges/neurips-2022-minerl-basalt-competition), and it would be awesome to use the HF ecosystem.