Concepts component should collapse and expand the examples

[gregwhitworth]

While the concepts section is useful, it can make scrolling really long on large components and make navigating the page a chore. I have a recommendations to remedy this.

• Make it so that the labels toggle the visibility of the concepts from the different libraries.

A good example of where this would be helpful is on the datepicker research page.

The research is great but it's hard to see where one concept starts and another ends.

[gregwhitworth]

@assuncaocharles any chance you might be able to take a look at fixing this? You seem pretty knowledgeable with react.

[assuncaocharles]

@gregwhitworth Fixed, PR linked