Rename ansible groups to use _ instead of - (#7552)

* rename ansible groups to use _ instead of -

k8s-cluster -> k8s_cluster
k8s-node -> k8s_node
calico-rr -> calico_rr
no-floating -> no_floating

Note: kube-node,k8s-cluster groups in upgrade CI
      need clean-up after v2.16 is tagged

* ensure old groups are mapped to the new ones

roles/kubernetes/kubeadm/templates/kubeadm-client.conf.v1beta2.j2

@@ -21,7 +21,7 @@ caCertPath: {{ kube_cert_dir }}/ca.crt
 nodeRegistration:
   name: {{ kube_override_hostname }}
   criSocket: {{ cri_socket }}
-{% if 'calico-rr' in group_names and 'kube-node' not in group_names %}
+{% if 'calico_rr' in group_names and 'kube_node' not in group_names %}
   taints:
   - effect: NoSchedule
     key: node-role.kubernetes.io/calico-rr