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-gce.j2

@@ -12,7 +12,7 @@
 [kube_control_plane]
 {{node1}}
 
-[kube-node]
+[kube_node]
 {{node2}}
 
 [etcd]
@@ -23,7 +23,7 @@
 {{node1}}
 {{node2}}
 
-[kube-node]
+[kube_node]
 {{node3}}
 
 [etcd]
@@ -41,7 +41,7 @@
 [kube_control_plane]
 {{node1}}
 
-[kube-node]
+[kube_node]
 {{node2}}
 
 [etcd]
@@ -50,24 +50,24 @@
 [kube_control_plane]
 {{node1}}
 
-[kube-node]
+[kube_node]
 {{node1}}
 
 [etcd]
 {{node1}}
 {% endif %}
 
-[k8s-cluster:children]
-kube-node
+[k8s_cluster:children]
+kube_node
 kube_control_plane
-calico-rr
+calico_rr
 
-[calico-rr]
+[calico_rr]
 
 {% if mode is defined and mode in ["scale", "separate-scale", "ha-scale"] %}
 [fake_hosts]
 fake_scale_host[1:200]
 
-[kube-node:children]
+[kube_node:children]
 fake_hosts
 {% endif %}