hardcoded "portal" subdomain in nubus deployments

[l-jonas]

See here. This assumes that the nubus subdomain is "portal" while the actual value (that can be different) could be read from {{ include \"stack-data-ums.subDomains.portal\" . }} or something else.

[l-jonas]

This is part of OpenDesk Deployment Issue 193 - Default portal subdomain being used instead of user defined subdomain in ums configmaps