Prepare defaults and vars

Especially to be conform to RFC 2142 there are some predefinitions
needed
Also we need to make sure that those always are applied except they are
explicitly overwritten

https://tools.ietf.org/html/rfc2142

tasks/main.yml

@@ -39,6 +39,8 @@
 
 # For the other files the we get a key-value pair with the dotqmail extention
 # as key and the list of lines as value while looping over dotqmail_files
+# (which is a combination of dotqmail_config_files from inventory over
+# dotqmail_default_files from role defaults)
 - name: generate/update other dotqmail-files
   template:
     src: templates/dotqmail.j2