Add a flag to enable cloud DNS when creating cluster

[dannikay]

Features

This PR adds a flag to enable cloud DNS when creating cluster. Without this flag, it took another 10s of minutes to enable Cloud DNS after cluster construction is complete.

Testing / Documentation

xpk cluster delete --cluster=${CLUSTER} --zone=${ZONE} --project=${PROJECT} --force
xpk cluster create-pathways \
--num-slices=${CLUSTER_NODEPOOL_COUNT} \
--tpu-type=${TPU_TYPE} \
--pathways-gce-machine-type=${PW_CPU_MACHINE_TYPE} \
--cluster-cpu-machine-type=${PW_CPU_MACHINE_TYPE} \
--project=${PROJECT} \
--zone=${ZONE} \
--default-pool-cpu-num-nodes=1 \
--cluster=${CLUSTER} \
--custom-cluster-arguments="--network=${NETWORK} --subnetwork=${SUBNETWORK} --enable-ip-alias --cluster-dns=clouddns --cluster-dns-scope=vpc"

Output:

...
[XPK] GKE commands done! Resources are created.
[XPK] See your GKE Cluster here: https://console.cloud.google.com/...
[XPK] Exiting XPK cleanly

• [ y ] Tests pass
• [ y ] Appropriate changes to documentation are included in the PR

[pawloch00]

please use local branch instead of fork

[dannikay]

please use local branch instead of fork

I'm afraid that I may not have the write permission to the main repo. Please advise.

[dannikay]

A friendly reminder for review~

[scaliby]

Why is this needed? Isn't checking if coredns deployments exist enough?

[dannikay]

Why is this needed? Isn't checking if coredns deployments exist enough?

My understanding is that without it, it will create core DNS deployment which conflicts with CloudDNS.