[web] [refactor] change input buttons to <Button /> component

Summary:
Replace all input elements that are submit buttons with HTML Button components. Right now all of the styling is still very off. We should use button elements and our button component in general.

before:

danger:

gif:

Test Plan: Make sure functionality still works. I tested the button elements and they all seem to be working.

Reviewers: atul, def-au1t, palys-swm

Reviewed By: palys-swm

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

Differential Revision: https://phabricator.ashoat.com/D3425