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

facts.yml

@@ -1,6 +1,6 @@
 ---
 - name: Gather facts
-  hosts: k8s-cluster:etcd:calico-rr
+  hosts: k8s_cluster:etcd:calico_rr
   gather_facts: False
   tasks:
     - name: Gather minimal facts