Simple changes to the Sign-In / Sign-Up views in the UI to add a route parameter (e.g. "?rd=<quickstart_url>")

Sign-In:
If "rd" route parameter is supplied, UI should redirect the user there upon successful login

Sign-Up:
If "rd" route parameter is supplied, UI should forward this parameter as the "nexturl" field so that the API server knows to include it in the account approval e-mail (see NDS-1099)

Assumed in this ticket is that the LoginModule (post-refactor) is smart enough to preserve "?rd=" during navigation within the module (e.g. from Sign-In to Sign-Up)