GKE: Enable integration tests (#214)

* GKE: Enable integration tests

Signed-off-by: Sameer Naik <[email protected]>

* fix GKE integration test setup

Signed-off-by: Sameer Naik <[email protected]>

* let gke select the latest available k8s patch release

* define `waitForRollout` utility function

* drop `+k8s` string from platform name

* insert the random string before the platform substring

* wait for deployments in `kube-system` namespace to rollout

* fix command to delete dns zone

* remove `--async` flag from GKE cluster deletion

when the cluster is delete synchronously the dns zone gets cleaned up
and the subsequent call to delete the zone executes successfully.

* fix gke disk leakage

* break multiline command block

* purge zone records before deleting the zone

* cleanup `gcloud container clusters create` command

* remove double dashes from clusterName

* add utility functions to update glue records

* setup glue records for gke tests

* remove `--dns-suffix` requirement for monitoring tests

* specify machine-type in gke cluster create command

* let kubeprod create the dns zone

* nameServers as a ArrayList to insertGlueRecords