This diff is the second part to updating the `Header` component to match the redesigns. The foucs of this diff is to introduce and layout the new elements needed for the header redesign. The new elements include:
# Beta Badge
# Team and Investors page nav replacing the App page nav
In this diff I also updated any typography/colors to use our design system created by Ted. I did not update the Github/Twitter colors, because those are one off instances that probably won't ever need to change, but if we want to create variables for them, I can do that.
Depends on D7835