Remove DISABLE_AUTH param?

[landonreed]

We should determine if we want to keep DISABLE_AUTH as a config param. Since we now have end to end tests that rely on Auth0, perhaps we should just let test classes separately set this value and have the application respond accordingly.

There may be other arguments for keeping it, however, e.g., if we need to run the application without authentication, but auth is such a crucial part of this application that I can't see that necessarily being needed.