SIENTIAPDE-1082

Implement shutdown methods for Activities and Kafka; enhance error handling in worker main function

scouter/activities/activities.py

@@ -65,3 +65,7 @@ class Activities(Postgres, Redis, Kafka, Gates):
     @activity.defn(name="prepare_activity")
     async def prepare_activity(self, input_data: dict[str, Any]):
         await super().prepare_activity(input_data)
+
+    def shutdown(self):
+        Postgres.close(self)
+        Kafka.close(self)