Add HostnameNetworkConfigMap output

This output will map server names to their NetworkConfig resource id.
This makes it easy to retrieve the NetworkConfig resource for each
server in the config-download code.

Change-Id: I315f2e2eb880e9f3cb67d9f4cdc789f08c6c4021
implements: blueprint reduce-deployment-resources

overcloud.j2.yaml

@@ -1192,3 +1192,11 @@ outputs:
   GlobalConfig:
     description: The global_config (hieradata).
     value: {get_attr: [GlobalConfig, value]}
+  HostnameNetworkConfigMap:
+    description: Mapping of hostname to NetworkConfig resource
+    value:
+      map_merge:
+        list_concat:
+{%- for role in roles %}
+          - {get_attr: [{{role.name}}, hostname_network_config_map]}
+{%- endfor %}

puppet/role.role.j2.yaml

@@ -838,6 +838,13 @@ outputs:
   {%- endfor %}
       ctlplane: {get_attr: [NetHostMap, value, ctlplane, fqdn]}
       canonical: {get_attr: [NetHostMap, value, canonical, fqdn]}
+  hostname_network_config_map:
+    description: Mapping of hostname to NetworkConfig resource
+    value:
+      map_replace:
+        - HOSTNAME: {get_resource: NetworkConfig}
+        - keys:
+            HOSTNAME: {get_attr:[{{server_resource_name}}, name]}
   hosts_entry:
     value:
       str_replace: