    First version.
    First version.

    Module for Prosody IM (https://prosody.im) to allow authentication against a
    Zimbra server.
    For authentication POP3 is being used - right now ONLY clear text POP3 is
    implemented/tested, so make sure that you have a secure and trusted network
    path between the Prosody and the Zimbra POP3 server!
    For user lookup SSH is being used - for this to work the user "prosody" needs
    to have:
    a) A SSH key which can be created like this (as root):
       if [ ! -s /var/tmp/zimbra_key ]
       then
           ssh-keygen -b 2048 -C prosody -f /var/tmp/zimbra_key
       fi
       chown prosody /var/tmp/zimbra_key*
       cat << EOT
       Please copy the contents of /var/tmp/zimbra_key.pub
       into /opt/zimbra/.ssh/authorized_keys on the Zimbra server:

       EOT
       cat /var/tmp/zimbra_key.pub

    b) The public part of the key in the file /opt/zimbra/.ssh/authorized_keys
       on the Zimbra server

    c) The module needs to be enabled in prosody configuration (global or per
       virtualhost), example:

       -- Use Zimbra authentication module
       authentication = "pop3";
       zimbra_auth_host = "192.168.1.110";
       -- Optional: zimbra_pop3_port = "110";

Change-Id: I4210ec71ce9307a8b04905fc5a00abfd6a9554ec

B-LUC/AdminTools,B-LUC/AdminTools