Mailsetup Migration from mailcow to mailu

Rebuild the whole mail setup to be based on mailu

webserver/docker_mail/templates/mailu/overrides/postfix/transport.map

+yahoo.com	polite:
+hotmail.com	polite:
+outlook.com	polite:
+exchange.com	polite:
+microsoft.com	polite:
+1und1.de	polite:
+t-online.de	polite:
+web.de		polite:
+gmail.com	polite: