host_interface: use correct table in VA map
added 404-exception to use when the requested resource could not be found
added a Config API to get config files for a given Host/OS combo
added Debian config-generator infrastructure
added Config generator for Debian /etc/network/interfaces
added Action frontend for APIs.

This is supposed to be the entry point for everything that "does" something, whereas the direct object endpoints like Host, Host_Interface etc. are supposed to be used only for storing the description of something