Remove versions from inventory sample (#12164)

The recommended usage of kubespray is to use the default versions.
So putting them in inventory/sample is not really very helpful, and
causes:
- churn (keeping the inventory/sample up to date)
- support issues (mismatch between defaults and sample inventory)

Remove all concrete versions from the inventory sample.

inventory/sample/group_vars/k8s_cluster/addons.yml

@@ -148,7 +148,6 @@ cert_manager_enabled: false
 metallb_enabled: false
 metallb_speaker_enabled: "{{ metallb_enabled }}"
 metallb_namespace: "metallb-system"
-# metallb_version: 0.13.9
 # metallb_protocol: "layer2"
 # metallb_port: "7472"
 # metallb_memberlist_port: "7946"
@@ -210,7 +209,6 @@ metallb_namespace: "metallb-system"
 #             - pool2
 
 argocd_enabled: false
-# argocd_version: 2.14.5
 # argocd_namespace: argocd
 # Default password:
 #   - https://argo-cd.readthedocs.io/en/stable/getting_started/#4-login-using-the-cli