Neko : Add more details on datasets

[bhavul]

Ideally instead of the simple bullet list, it would be useful to have a table defining a few key things about the datasets.

As an example, this could look like this but we can iterate and add/modify anythings in the design:

Dataset	Source	Size	Approx # Tokens	Modalities	Remarks
Conceptual Captions	https://ai.google.com/research/ConceptualCaptions/	X GB/TB	XYZ

This would help us identify the right datasets to include while training our Neko model.