Adds notification stats update into the callback process

- when a provider callback occurs and we update the status of the notification, also update the statistics table

Adds:
- Mapping object to the clients to handle mapping to various states from the response codes, this replaces the map.
- query lookup in the DAO to get the query based on response type / template type

Tests around rest class and dao to check correct updating of stats

Missing:
- multiple client callbacks will keep incrementing the counts of success/failure. This edge case needs to be handle in a future story.

app/clients/__init__.py

@@ -13,6 +13,11 @@ class Client(object):
     pass
 
 
+STATISTICS_REQUESTED = 'requested'
+STATISTICS_DELIVERED = 'delivered'
+STATISTICS_FAILURE = 'failure'
+
+
 class ClientResponse:
     def __init__(self):
         self.__response_model__ = None
@@ -24,7 +29,6 @@ class ClientResponse:
         return self.response_code_to_object(response_code)['message']
 
     def response_code_to_notification_status(self, response_code):
-        print(response_code)
         return self.response_code_to_object(response_code)['notification_status']
 
     def response_code_to_notification_statistics_status(self, response_code):