Goal: 

• We'd like users to use a shared EPEL repository instead of creating a custom EPEL repository via the popular repos tab.

Acceptance Criteria:

• Remove the popular repositories tab
• Replace the “Custom | Red Hat” filter with a multi-select filter that says “Custom |  EPEL | Red Hat”
• Filter should select Custom and EPEL by default, so clicking into the app from the zero state shows the EPEL repos
• Do not allow the user to create, edit, or delete an EPEL repository
• Update zero state to remove popular repos