Feature #2438 add support for lmtp delivery to downstream servers
new feature lmtp support for simplifying setups
with lmtp capable downstream servers (e.g. dovecot)
Postfix support lmtp out of the box and can now deliver
mails directly to internal mailbox servers without
one more smtp connection
extending the gui code for new lmtp option:
MailProxyConfiguration & MailProxyConfiguration:Transport:
Adding combobox "smtp" / "lmtp" as a new option
Generalizing some "SMTP" keywords