this PR adds a service ClusterIP to reach skipper-ingress within the cluster to get the full power of skipper-ingress route defintions from inside the cluster.
this PR adds a service ClusterIP to reach skipper-ingress within the cluster to get the full power of skipper-ingress route defintions from inside the cluster.

* ingress flow https://my-app.my-acc.zalan.do/ : client -> ALB -> skipper-ingress -> my-app svc -> my-app pod
* svc flow: http://my-app.default.cluster.local/: client -> my-app svc -> my-app pod
* new cluster internal: curl -H "Host: my-app.my-acc.zalan.do" http://skipper-ingress.kube-system.cluster.local/
* new skipper-svc flow:  skipper svc -> skipper-ingress -> my-app svc -> my-app pod

zalando-incubator/kubernetes-on-aws,zalando-incubator/kubernetes-on-aws,zalando-incubator/kubernetes-on-aws