[Bug] CoreDNS installation uses deprecated kubernetes deployment scripts

XPK's CoreDNS installation uses the deprecated deployment method from [github.com/coredns/deployment](https://github.com/coredns/deployment/tree/master/kubernetes), which has been superseded by the official Helm chart.
>These kube-dns/CoreDNS migration scripts and templates are deprecated. For deploying coredns, use the coredns helm chart, or the yaml templates maintained by kubeadm.

### Current Behavior

```bash
git clone https://github.com/coredns/deployment.git /tmp/deployment
./deploy.sh | kubectl apply -f -
```

### Expected Behavior

Use the official Helm chart as recommended:\
```bash
helm repo add coredns https://coredns.github.io/helm
helm --namespace=kube-system install coredns coredns/coredns \
--set replicaCount=15
```