example-config: Moved ACL settings to a separate .conf file. --HG-- branch : HEAD

example-config: Moved quota configuration to a separate .conf file and improved the comments. --HG-- branch : HEAD

example-config: Added nn- prefix to *.conf files so the sort ordering makes more sense. This is especially important to get mail_plugins = $mail_plugins example working in protocol sections. --HG-- branch : HEAD