Add map merge strategy for {{role.name}}Parameters

This would allow role specific parameters to be defined
in multiple environment files and would be merged. It
would throw an error if the merge strategy is not defined
in an environment file.

Closes-Bug: #1913701
Change-Id: Ifdb1dec4e9149c7e3e3df72020adad8a7a5f6032

overcloud-resource-registry-puppet.j2.yaml

@@ -354,6 +354,9 @@ resource_registry:
 parameter_merge_strategies:
   ServiceNetMap: merge
   VipSubnetMap: merge
+{% for role in roles %}
+  {{role.name}}Parameters: merge
+{% endfor %}
 
 parameter_defaults:
   NeutronMechanismDrivers: ovn
@@ -366,6 +369,7 @@ parameter_defaults:
   # Parameters generated for {{role.name}} Role
   {{role.name}}Services: {{role.ServicesDefault|default([])}}
   {{role.name}}NetworkDeploymentActions: []
+  {{role.name}}Parameters: {}
 {% endfor %}
 
   ServiceNetMap: