Add all-in-one node definition

Adds an all-in-one node class definition to core.pp and a
corresponding example node definition in site.pp.  This allows
creation of a node that runs all basic OpenStack functions.

Implements: blueprint openstack-all-in-one

Note that this depends on an upstream change which has now been accepted and merged into our repos both for Havana and Grizzly:
https://review.openstack.org/#/c/46345/
https://review.openstack.org/#/c/46306/