Update Navigation

[Raphael-Hyde]

After the redesign of COVIDcast we'll want to update the naming in the dropdown menu. Here's a propose for the new labels:
https://docs.google.com/presentation/d/1n7U0js9h5dslT-uD9t5A_oaF9Ljaztl939lVIbdbkAA/edit#slide=id.gc34bfe52d9_0_6

Figma mock: https://www.figma.com/file/IiYu74VmEi4GVS4bnYaTd6/Delphi-Site-Redesign?node-id=2626%3A0