Proposing fixes for contrib/terraform/vsphere/ #8436 (#8441)

* fixes issues in vSphere Terraform contrib. #8436

* fix formatting

* add variables to the main module and document changes

* add missing newline

contrib/terraform/vsphere/modules/kubernetes-cluster/templates/vapp-cloud-init.tpl

@@ -0,0 +1,24 @@
+#cloud-config
+
+ssh_authorized_keys:
+%{ for ssh_public_key in ssh_public_keys ~}
+  - ${ssh_public_key}
+%{ endfor ~}
+
+write_files:
+  - path: /etc/netplan/10-user-network.yaml
+    content: |.
+      network:
+        version: 2
+        ethernets:
+          ${interface_name}:
+            dhcp4: false #true to use dhcp
+            addresses:
+            - ${ip}/${netmask}
+            gateway4: ${gw} # Set gw here
+            nameservers:
+              addresses:
+              - ${dns} # Set DNS ip address here
+
+runcmd:
+  - netplan apply