title: How to send email verification code to user email in firebase
body: <p>I want to send email verification code to user's email using firebase authentication. I am using <em>(sendEmailVerification)</em> method but firebase sends a verification link to user's email. Is it possible to send verification code to user's email if yes then how it can be done?</p>
  
  <p>I am using Angular 4 and for firebase angularfire2</p>
  
  <p>Thanks.</p>