Add bearer token authentication to Vagrant clusters

This does not remove basic authentication in Vagrant clusters.
Users will still be able to authenticate with username=vagrant, password=vagrant

cluster/vagrant/util.sh

@@ -162,6 +162,7 @@ function echo-kube-env() {
   echo "MASTER_PASSWD='${MASTER_PASSWD}'"
   echo "KUBE_USER='${KUBE_USER}'"
   echo "KUBE_PASSWORD='${KUBE_PASSWORD}'"
+  echo "KUBE_BEARER_TOKEN='${KUBE_BEARER_TOKEN}'"
   echo "ENABLE_CLUSTER_MONITORING='${ENABLE_CLUSTER_MONITORING}'"
   echo "ENABLE_CLUSTER_LOGGING='${ENABLE_CLUSTER_LOGGING:-false}'"
   echo "ELASTICSEARCH_LOGGING_REPLICAS='${ELASTICSEARCH_LOGGING_REPLICAS:-1}'"
@@ -275,6 +276,7 @@ function verify-cluster {
 # Instantiate a kubernetes cluster
 function kube-up {
   load-or-gen-kube-basicauth
+  load-or-gen-kube-bearertoken
   get-tokens
   create-provision-scripts