Need README Page for Datasets

[colinthebomb1]

After getting feedback on the jail hub, the need for dataset documentation was brought up by Social Science researchers. Adding a README page will make datasets and workflows more accessible and understandable for users trying to view and edit existing workflows. The README will use a lightweight code editor and markdown renderer, and will be similar to Kaggle dataset README.

Design document

[bobbai00]

Please include your design doc's link in the issue.