[Mailmunge] Process "outgoing" vs "incoming"

[postfix at ptld.com]

> The "daemon_port" macro is passed by default, so you should be able to
> inspect that; it will probably be 25 for "inbound" and 465 or 587 for
> "outbound".  Presumably, the submission port is only used for outbound
> mail and always requires auth.


FYI, while experimenting with the port i also discovered that 
$ctx->sendmail_macro('auth_authen') is also passed by default and 
available in filter_message() and filter_wrapup() which is perfect 
having both port and SASL login to confirm an "outgoing" email.