List support in table cells

[shainaraskas]

We often need to share a short list of info in a tabular format, but our tables don't support lists.

gh gets around this by allowing for html lists inside of markdown tables (ugly but functional)

we currently work around it using - and <br> but this is not ideal because list items don't wrap properly / use non-standard bullets

example

https://elastic.github.io/docs-builder/versions/#versioning-facets
https://elastic.github.io/docs-builder/versions/#content-patterns

Related to #112