Detect coredns or kubedns service, populate in service definition yaml

[JamesTGrant]

modified file name to reove kube-dns service name assumption (could be coredns or kube-dns). Added check in install.sh to look through kube-system service list and match coredns or kube-dns. Set the result as a variable and use that variable in the uncached service definition service

[axot]

Hi @JamesTGrant,

Thank you for the contribution, could you share about how did you install CoreDNS? According to official CoreDNS addon, the service name should consistent using kube-dns. We want to know the use case for a better decision making. https://github.com/kubernetes/kubernetes/blob/master/cluster/addons/dns/coredns/coredns.yaml.sed#L192

Kind Regards,