Block the creation of a user if sending a password-reset email would be ineffective

When creating a user, the administrator has the option to send an email to the new user's email address so that he can set his or her password.

However, for a user created in a Internal with LDAP authentication directory, the email will be ineffective because the user's password is set in LDAP and not Stash. (Contrary to JIRA or Confluence, Stash disables write access to remote user directories. As a result, Stash cannot remotely set the user's password in LDAP).