Add Hirschmann HiOS and ssh login banner autodetection

[mpfz0r]

Tested with a Hirschmann BRS-20

Add a new auto-detection method: _autodetect_login_banner

Some devices directly reveal their identity via a login banner.
e.g.

[email protected]'s password: 


         Copyright (c) 2011-2019 Hirschmann Automation and Control GmbH

                             All rights reserved

                       BRS20-0400 Release HiOS-2S-08.1.00

                          (Build date 2019-12-03 06:58)


                    System Name   :  BRSX-6460380C27
                    Management IP :  192.168.88.10
                    Subnet Mask   :  255.255.255.0
                    Base MAC      :  64:60:38:0C:27:XX
                    USB IP        :  192.168.248.100
                    USB Mask      :  255.255.255.0
                    System Time   :  2019-01-01 03:00:08


NOTE: Enter '?' for Command Help.  Command help displays all options
      that are valid for the particular mode.
      For the syntax of a particular command form, please
      consult the documentation.

!*(BRS)>

we can match that HiOS release string directly without issuing a command.

[ktbyers]

Looks good.