Load all template model relationships when archiving a service

Since the version classes hinge on delicately preserving the session,
we need to take lots of care to ensure that we don't accidentally flush
half-way through. By joinedloading the template_redacted beforehand,
we prevent a flush which would inadvertantly remove the Service object
from the session, while it's still waiting in line to be versioned.

app/dao/services_dao.py

@@ -111,6 +111,7 @@ def dao_archive_service(service_id):
     # to ensure that db.session still contains the models when it comes to creating history objects
     service = Service.query.options(
         joinedload('templates'),
+        joinedload('templates.template_redacted'),
         joinedload('api_keys'),
     ).filter(Service.id == service_id).one()