Need different hostname convention for portal backends

[daveyu]

https://github.com/cloudposse/charts/blob/master/incubator/portal/templates/proxy.ingress.yaml#L47 sets backend hosts like dashboard.portal.us-west-2.staging.example.com, but I want the option for it to be dashboard-portal.us-west-2.staging.example.com. The reason is so we can just use a SAN cert for *.us-west-2.staging.example.com.

[osterman]

@daveyu this looks like an easy fix.

@goruha make "%s.%s" a template string in values.yaml that defaults to %s.%s. Then @daveyu can override this with %s-%s. Do you think that will work?

For some background, @daveyu has had to rollout ACM in place for kube-lego for stability to avoid risk of any rate-limiting. Since they are using ACM, they need to be more strategic about how they name their hosts so they comply with the wildcard certificate.