Use react-router Link for nav
Use react-router-dom's Link component for the top nav tabs instead of div elements with onClick.
After this, I'll put up a diff that allows disabling the nav items as needed.
Stacked on D4459.
Test Plan: Verify proper rendering, behavior, and navigation of nav link items.
Reviewers: bengotow, prha, alangenfeld
Reviewed By: prha
Differential Revision: https://dagster.phacility.com/D4460