notifications, when retrieved by notification id, or service id (i.e.
all notifications for service).
There is a new element returned at top level of notification json called
body, which is the template content merged with personalisation. This
is consistent with api to endpoint to create notification which returns
what was sent as 'body' in json response.
Merging of template with personalisation is done in the
NotificationStatusSchema.
Personalisation data in encrypted before storing in db.
