Ticket 389ds #48450 - Implement systemd password support for svrcore
    
    Bug Description:  Svrcore is a secure password collection system. Is is used by
    389 Directory Server to collect a pin from a text file, or if not avaliable,
    it will ask the user. However, during system start up a tty is not always
    avaliable to the user.
    
    Fix Description:  This implement support for systemd's ask-password api as a
    client. Additionally, we implement detection of tty connection to the user
    module to help improve this. As a result, when a binary is run on the command
    line, it will prompt using existing methods. If the tty is not avaliable, it
    will contact systemd, which logs a wall message for the user to input a password
    
    If the service is started from systemd, it will be integrated to the startup
    command, IE:
    
    $ systemctl start test-interactive.service
    Enter PIN for internal (software): *****
    
    https://fedorahosted.org/389/ticket/48450
    
    Author: wibrown
    
    Review by: nhosoi (Thanks!)