Support Ingress hostnames in addition to IP addresses

Not all Kubernetes loadbalancers return IP addresses. Some return DNS names, like Amazon ELB's. For example: asdfasdfasdf-asdf.us-east-1.elb.amazonaws.com. This field is correctly shown on as the External Address of the NGINX Ingress service using kubectl, but it does not display in GitLab's UI.

We should update our Ingress deployment to include supporting DNS names. The text should probably also be something like External Address.