Add category icons

[marcbouchenoire]

Add category icons which scroll to their category when clicked and become active depending on the scroll position.

[revogabe]

Hi, @marcbouchenoire Can I just work on a solution and submit the PR or do I need to ask you to sign me to this issue?

[marcbouchenoire]

Hey @revogabe, feel free to take a stab at it in a PR!

[thisislvca]

This would be sick to have! I just spent an hour trying to get emoji mart to work, and it's been a nightmare - thanks for this great package guys!

[andreasvirkus]

I've created a first draft/proposal for this in #29, had some questions @marcbouchenoire 🙏