Support Calico advertisement of MetalLB LoadBalancer IPs (#7593)

* add initial MetalLB docs

* metallb allow disabling the deployment of the metallb speaker

* calico>=3.18 allow using calico to advertise service loadbalancer IPs

* Document the use of MetalLB and Calico

* clean MetalLB docs

inventory/sample/group_vars/k8s_cluster/addons.yml

@@ -132,6 +132,7 @@ cert_manager_enabled: false
 
 # MetalLB deployment
 metallb_enabled: false
+metallb_speaker_enabled: true
 # metallb_ip_range:
 #   - "10.5.0.50-10.5.0.99"
 # metallb_speaker_nodeselector:

inventory/sample/group_vars/k8s_cluster/k8s-net-calico.yml

@@ -50,6 +50,11 @@
 # - x.x.x.x/24
 # - y.y.y.y/32
 
+# Adveritse Service LoadBalancer IPs
+# calico_advertise_service_loadbalancer_ips:
+# - x.x.x.x/24
+# - y.y.y.y/16
+
 # Choose data store type for calico: "etcd" or "kdd" (kubernetes datastore)
 # calico_datastore: "kdd"