refactor(gatsby-remark-api-table): Replace documentation with the use of react-docgen

[matuzalemsteles]

WIP/Draft

This is experimental and the implementation is very simple yet, there are many improvements that we can implement in the API table experience.

I used react-docgen directly because it recently released a beta version with TypeScript support and gatsby-transformer-react-docgen is still with the old implementations.

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See example: Date Picker API Table

[coveralls]

Pull Request Test Coverage Report for Build 2692

• 1 of 1 (100.0%) changed or added relevant line in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 82.271%

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Totals
Change from base Build 2687:	0.0%
Covered Lines:	1219
Relevant Lines:	1390

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💛 - Coveralls

[bryceosterhaus]

One thing I noticed is the type will often reference our interface's name, this seems like it might be unhelpful unless we can link to the definition of that interface. What do you think?

[matuzalemsteles]

@bryceosterhaus yeah, I thought to do that too, I think a great idea, react-docgen is implementing logic to get the imported reactjs/react-docgen#352 types, this can help us create this. We still have to think about how we are going to show the information of another type on the screen.

[matuzalemsteles]

hey guys, I've made some improvements here to prepare for the alpha release. I'm merging this so we can gather feedback during this time.