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

contrib/network-storage/heketi/inventory.yml.sample

@@ -3,7 +3,7 @@ all:
         heketi_admin_key: "11elfeinhundertundelf"
         heketi_user_key: "!!einseinseins"
     children:
-        k8s-cluster:
+        k8s_cluster:
             vars:
                 kubelet_fail_swap_on: false
             children:
@@ -13,7 +13,7 @@ all:
                 etcd:
                     hosts:
                         node2:
-                kube-node:
+                kube_node:
                     hosts: &kube_nodes
                         node1:
                         node2: