title: firebase users login through mobile
body: <p>I'd like to know if it's possible for a mobile registered firebase user to log-in without authentication procedure, in other words: </p>
  
  <p>Lets say an administrator creates a firebase user by console (or web interface to console) then is it possible that when this user launches the app on his mobile he just logs in without the authentication procedure?</p>
  
  <p>To put it simple, is it possible for mobile users a log-in like  email/password user: just enter the number and log-in?</p>