qhub upgrade oauth_callback_url/scopes and 0.4 version [bug]

[danlester]

As @iameskild noted, the qhub upgrade command needs to have its 0.3.14 code section updated to be 0.4 (0.3.14 is no longer the current release, and 0.3.14 was released without any upgrade capability, as a patch on 0.3.13).

It also needs to remove oauth_callback_url and scopes fields, if present, for Auth0 and GitHub authentication modes.

And the qhub upgrade to 0.4 should inform the user to change the auth0/github callback URLs in the relevant clients, if appropriate.