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/group_vars/k8s_cluster/k8s-net-canal.yml

@@ -0,0 +1,10 @@
+# see roles/network_plugin/canal/defaults/main.yml
+
+# The interface used by canal for host <-> host communication.
+# If left blank, then the interface is choosing using the node's
+# default route.
+# canal_iface: ""
+
+# Whether or not to masquerade traffic to destinations not within
+# the pod network.
+# canal_masquerade: "true"