Add events aggregator

Hcs.WebApp/BackgroundServices/Delegates.cs

@@ -0,0 +1,8 @@
+namespace Hcs.WebApp.BackgroundServices
+{
+    public delegate void OperationStarted(int operationId, int campaignId, DateTime startedAt);
+
+    public delegate void OperationExecuted(int operationId, int campaignId, string messageGuid);
+
+    public delegate void OperationEnded(int operationId, int campaignId, DateTime endedAt, string failureReason);
+}