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/azurerm/roles/generate-inventory_2/templates/inventory.j2

@@ -21,14 +21,14 @@
 {% endif %}
 {% endfor %}
 
-[kube-node]
+[kube_node]
 {% for vm in vm_roles_list %}
-{% if 'kube-node' in vm.tags.roles %}
+{% if 'kube_node' in vm.tags.roles %}
 {{ vm.name }}
 {% endif %}
 {% endfor %}
 
-[k8s-cluster:children]
-kube-node
+[k8s_cluster:children]
+kube_node
 kube_control_plane