Example of passing per-node config data in pre_deploy config

Example of passing per-node config data in pre_deploy config

Shows one method of passing a map of data in to the pre_deploy extraconfig
interface, such that it could be used in combination with
https://review.openstack.org/#/c/215013/ to create a node uuid specific
hieradata file, or to perform some other non-puppet per-node configuration.

This would be used by specifying an environment file like:
resource_registry:
      OS::TripleO::ControllerExtraConfigPre: puppet/extraconfig/pre_deploy/per_node.yaml
parameter_defaults:
      NodeDataLookup: |
        {"AB4114B1-9C9D-409A-BEFB-D88C151BF2C3": {"foo": "bar"},
         "8CF1A7EA-7B4B-4433-AC83-17675514B1B8": {"foo2": "bar2"}}

Change-Id: I62e344669e0ca781dd93d3f7d2190b70299877c2