Add one_off filter when getting all notifications for a service

Added the option to filter by one_off messages to the DAO function
`get_notifications_for_service`. Previously, one-off notifications
were not returned - this has changed so that the default is for
one-off notifications to be returned. Also simplified the `include_jobs`
filter for this function.

The DAO function gets used in 3 places - for the V1 and V2 API endpoints,
which will now start to return one-off messages. It also gets used by
the admin app which needs to pass in `include_one_off=False` to the
`get_all_notifications_for_service` where we don't want one-off
notifications to show, such as the API message log page.

tests/app/db.py

@@ -176,7 +176,8 @@ def create_notification(
         normalised_to=None,
         one_off=False,
         sms_sender_id=None,
-        reply_to_text=None
+        reply_to_text=None,
+        created_by_id=None
 ):
     if created_at is None:
         created_at = datetime.utcnow()
@@ -221,7 +222,8 @@ def create_notification(
         'international': international,
         'phone_prefix': phone_prefix,
         'normalised_to': normalised_to,
-        'reply_to_text': reply_to_text
+        'reply_to_text': reply_to_text,
+        'created_by_id': created_by_id
     }
     notification = Notification(**data)
     dao_create_notification(notification)