Refactor login route
Refactor login route

Just a little bit of cleanup to separate methods and async/await syntax.
I think this is more readable that the Ember.RSVP.defer syntax.

djvoa12/frontend,ilios/frontend,jrjohnson/frontend,gboushey/frontend,dartajax/frontend,djvoa12/frontend,ilios/frontend,dartajax/frontend,jrjohnson/frontend,thecoolestguy/frontend,thecoolestguy/frontend,gboushey/frontend