Collect new kinds of statistics for tracing distribution lists

[Paul Everitt]

Allow filtering and drill down, in all parts of the system, from inbound queue -> postoffice -> mailin -> mailout -> /etc/mail.log

- The sender of an incoming message

- Profile information of that sender (what groups they are in)

- Was the password expired at the time message arrived

- Does the sender have permissions to email to the target

We'll add more to this list as we brainstorm all the questions we'd like to ask.

[Carlos de la Guardia (cguardia)]

This will require adding this specific information to the logs, so that it can be extracted by graylog.