calico_version ineffective

Created by: garloff

As noted in the commit log to PR #304 (commit ce61c247445d1adfcc9ced3226012c7037746f7b), we currently have a parameter calico_version in the terraform which does control the version of the installed calicoctl binary, but not the more important kubernetes manifest calico.yaml. This is highly confusing and was not intended.

To fix this, do either:

• Drop calico_version (and just pick one that is validated -- might have a weak dependence on the k8s version)
• Make it effective by downloading the wanted version of calico.yaml (like we do for many other services). In this case, we should also add it to clusterctl.yaml (like the other services).