Add Tooling Section

[MicheleBertoli]

Following the discussions #62 in and #64, this PR implements a "Tooling" sections.
It also moves the babel plugin page from "Advanced" to "Tooling".

[kitten]

Nice! I really like the idea of having a separate section for tooling! It opens up the possibility of adding a lot more utilities in the future 🎉

I’m working on a new branch that switches all sections over to be written in markdown instead. Do you think we should merge this first and incorporate your changes into it? I’m not quite sure which way around it’s going to be easier, as there’s some miscellaneous changes in both #74

I’d probably say that we should merge this first?

[mxstbr]

Yesss this is super awesome!!

We want to integrate the docs for the stylelint processor too, and all the Babel plugin docs, so that in the end a) more people will find the tooling and b) it's all in one place 👌

[kitten]

I'll go ahead and merge the PR over at #77, which is this PR + the merged back changes 👍 😄

[MicheleBertoli]

Thank you very much @philpl @mxstbr