Fix heat plugin metadata for horizon

Define correct package name for heat horizon plugin. Setup policy metadata
in the same pillar file.

Related-Prod: PROD-19716

Change-Id: Ic8c380a1497c049092b70769bb974df897badf3f
diff --git a/horizon/server/plugin/heat.yml b/horizon/server/plugin/heat.yml
index 9e70480..909da66 100644
--- a/horizon/server/plugin/heat.yml
+++ b/horizon/server/plugin/heat.yml
@@ -5,7 +5,9 @@
         heat:
           source:
             engine: pkg
-            name: openstack-dashboard-heat-server-templates
-        horizon_overrides:
-          overrides:
-          - heat_server_templates
+            name: python-heat-dashboard
+      policy:
+        orchestration:
+          enabled: true
+          name: heat_policy.json
+          source: file