Adds Hiera YAML data for HA

- YAML data set
- Embedded (module-data)

Tested against RHOS5/RHEL7
I think this is in a reversed order? The ones at the top have the highest priority afaik.

Also i needed to add "classes" to the list so that hiera_include could find "HA_AIO_classes". And i added "custom" too, so that i could add my own overrides without interfering with the files under source control.