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

inventory/sample/inventory.ini

@@ -23,16 +23,16 @@
 # node2
 # node3
 
-[kube-node]
+[kube_node]
 # node2
 # node3
 # node4
 # node5
 # node6
 
-[calico-rr]
+[calico_rr]
 
-[k8s-cluster:children]
+[k8s_cluster:children]
 kube_control_plane
-kube-node
-calico-rr
+kube_node
+calico_rr