[SEO improvement] Add Dataset Metadata to make datasets indexable
Some people who host datasets on github seem to include a table of metadata at the end of their README.md to make the dataset indexable by [Google Dataset Search](https://datasetsearch.research.google.com/) (See [here](https://github.com/google-research/google-research/tree/master/goemotions#dataset-metadata) and [here](https://github.com/cvdfoundation/google-landmark#dataset-metadata)). This could be a useful addition to canonical datasets; perhaps even community datasets.

I'll include a screenshot (as opposed to markdown) as an example so as not to have a github issue indexed as a dataset:

> ![image](https://user-images.githubusercontent.com/3664563/144496173-953428cf-633a-4571-b75b-f099c6b2ed65.png)



**_PS: It might very well be the case that this is already covered by some other markdown magic I'm not aware of._**
