Fix Mailu configuration

Fixes #577 (closed)

Creates proper entrypoints in traefik to allow email traffic through, also correctly sets routers and services for mailu in docker-compose file. Added additional configuration settings for mailu to enable only ports that the user wants enabled. No sense in exposing ports that are not necessary or won't be used. 25 and 587 are used by default for sending/receiving... port 993 (secure imap) is also enabled by default. Added ports for bastion server to forward Fixed the config for the certdumper container.