[MlMt] Change Sender eMail for Mailing List

[lists.freron.com at nietzold.com]

** what i do:

i have the setting, that an reply email use the „send to“ email as 
„send from“ email adress (via adress pattern `.*@mydomain\.com` )

with an mailing list there is a group mail in the „send to“ field ( 
"MailMate Users" <mailmate at lists.freron.com> ) and not my eMail Adress.



** what i see:

when i reply to this mailing list email then my default email is used 
(because it not match the mailing list email)


** what i like:

i like to setup an „send from“ for this Mailing list ( or to use the 
real eMail which i found in the `X-Envelope-to:` mail header )