Add RVL-CDIP dataset
Resolves #2762 

Dataset Request : Add RVL-CDIP dataset [#2762](https://github.com/huggingface/datasets/issues/2762)
This PR adds the RVL-CDIP dataset.

The dataset contains Google Drive link for download and wasn't getting downloaded automatically, so I have provided manual_download_instructions.
- I have added the dummy_data.zip as well.

Needed inputs on how I can run the real data and the dummy data tests for datasets with manual download ?

Inputs and suggestions for improvement are welcome. Thank you.