[web] [chore] add icon types to Icons component

Summary: Type icon names, add auto-complete to icon component for better developer experience

Test Plan: flow shouldn't error out

Reviewers: atul, ashoat

Reviewed By: ashoat

Subscribers: ashoat, palys-swm, Adrian, karol-bisztyga

Differential Revision: https://phabricator.ashoat.com/D3250