Add support for additional configuration options to revaliases

[Syed-Shahrukh-OSSRevival]

https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=700847

A reverse alias gives the From: address placed on a user's outgoing messages
and (optionally) the mailhub these messages will be sent through.

Example: root:jdoe@isp.com:mail.isp.com

New feature suggests to accept auth_user, auth_pass and auth_method.

 if((p = strtok(NULL, " \t\r\n:"))) {
            if((auth_user = strdup(p)) == (char *)NULL) {
              die("revaliases() -- strdup() failed");
            }
            
            if((p = strtok(NULL, " \t\r\n:"))) {
              if((auth_pass = strdup(p)) == (char *)NULL) {
                die("revaliases() -- strdup() failed");
              }
            }
            
            if((p = strtok(NULL, " \t\r\n:"))) {
              if((auth_method = strdup(p)) == (char *)NULL) {
                die("revaliases() -- strdup() failed");
              }
            }
          }         

Further investigation is needed like there is a need to add additional parameter for handling TLS connections.