Add option to show OTP when adding host
    
    Add option to add host dialog which allows to show generated OTP.
    This patch also changed the way of informing user about success of adding host
    but only when the 'Generate OTP' option is checked. There is a new dialog with
    generated OTP.
    
    https://fedorahosted.org/freeipa/ticket/4602
    
    Reviewed-By: Petr Vobornik <pvoborni@redhat.com>