Enhance create_cluster.sh to handle slow infrastructure at stage `Waiting for Cluster=Ready` better

Created by: NotTheEvilOne

I'm facing some probably slow API responses after the latest changes for R5, maybe related to #552?

terraform_data.mgmtcluster_bootstrap_files (remote-exec): # Waiting for Cluster=Ready
terraform_data.mgmtcluster_bootstrap_files (remote-exec): error: no matching resources found

Running create_cluster.sh testcluster again results in:

# rendering clusterconfig from template
 Overwriting config for testcluster
 Warning: Cluster exists
 Hit ^C to interrupt
# Security groups for cilium
# apply configuration and deploy cluster testcluster
[...]
# Waiting for Cluster=Ready
kubeadmcontrolplane.controlplane.cluster.x-k8s.io/testcluster-control-plane condition met
machine.cluster.x-k8s.io/testcluster-control-plane-vhshr condition met
[...]

Has anyone else have seen this yet?