Investigate PropTypes documentation on docSite

The docSite doesn't currently show any propTypes info.

However it is documented by the Typescript interfaces.

We could...

• Read the *.propTypes property at runtime and generate a table from all of the keys/values, we'd have to work out how to add a description to each field (Ideally we want the description from a comment in the code...)
• Parse the typescript to get a list of propTypes and their associated comments (This might link to #31 (closed))

I would suggest we check what storybook do:

• https://github.com/styleguidist/react-docgen-typescript

This issue is to work out what the best approach is, get a feel for difficulty, and create issues to implement