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

tests/templates/inventory-aws.j2

@@ -6,7 +6,7 @@ node3 ansible_ssh_host={{ec2.instances[2].public_ip}} ansible_ssh_user={{ssh_use
 node1
 node2
 
-[kube-node]
+[kube_node]
 node1
 node2
 node3
@@ -15,12 +15,12 @@ node3
 node1
 node2
 
-[k8s-cluster:children]
-kube-node
+[k8s_cluster:children]
+kube_node
 kube_control_plane
-calico-rr
+calico_rr
 
-[calico-rr]
+[calico_rr]
 
 [broken_kube_control_plane]
 node2