Update doc and add release note about cdm-scoping

This patch updates document and add release note for cdm-scoping.

Change-Id: I8e9099aa5caf6bf17ea912e7b1a600af3b6d519d
Partially-Implements: blueprint cdm-scoping

doc/source/contributor/plugin/cdmc-plugin.rst

@@ -28,6 +28,8 @@ In order to create a new cluster data model collector, you have to:
 - Implement its :py:meth:`~.BaseClusterDataModelCollector.execute` abstract
   method to return your entire cluster data model that this method should
   build.
+- Implement its :py:meth:`~.BaseClusterDataModelCollector.audit_scope_handler`
+  abstract property to return your audit scope handler.
 - Implement its :py:meth:`~.Goal.notification_endpoints` abstract property to
   return the list of all the :py:class:`~.base.NotificationEndpoint` instances
   that will be responsible for handling incoming notifications in order to
@@ -57,6 +59,10 @@ Here is an example showing how you can write a plugin called
             # Do something here...
             return model
 
+        @property
+        def audit_scope_handler(self):
+            return None
+
         @property
         def notification_endpoints(self):
             return []
@@ -135,6 +141,10 @@ class method as followed:
             # Do something here...
             return model
 
+        @property
+        def audit_scope_handler(self):
+            return None
+
         @property
         def notification_endpoints(self):
             return []