Various Easy Performance Boosts

[kylemh]

Feature

Why is this feature being added?

1. Raven is a non-critical asset that is acting as render-blocking item. Make it async or defer it to get a faster "first paint".
2. react-table is an unused dependency.
3. notification.css is being requested separately from the main style bundle.

What should your feature do?

1. Use defer or async on Raven.
2. Delete everything referencing react-table
3. Bundle notification.css via import in src/index.js