Rename and reprioritize covidcast data in source selection menu #75
Description
The covidcast endpoint should be listed first in the epivis source selection tool. It is the most up-to-date and popular of our endpoints. It should also probably be marked as the "main" endpoint rather than "covidcast", since we're trying to move away from the "covidcast" terminology. I know space is limited in this display, but we've been calling it things like "the main Delphi endpoint (AKA covidcast)" or "formerly known as covidcast".
User story
It was hard for me to find the covidcast data in the source selection.
Additional context
