Open on page of passed-in emoji

[dancherb]

It would great if we could pass in an emoji when mounting the picker component so it opens on the page with that emoji. Say the user has already selected the "dog" emoji in our app, and then opens the picker again - it would then open on the page with the "dog" emoji instead of at the beginning again (lovely work by the way 🐶)

[pederjohnsen]

@dancherb sounds like an interesting idea, will consider, but atm will prioritise getting the lib up to date with emoji-mart and getting the lib out of beta and to v1, pull requests are always welcomed though if it's something you'd like to give a shot at or someone else! :)