ip -> ipv4...

...explictly label current ip values as ipv4, in order to more
easily add ipv6 support later on.

output.tf

@@ -1,16 +1,16 @@
-output "controlplanes_public_ip" {
+output "control_planes_public_ipv4" {
   value       = module.control_planes.*.ipv4_address
-  description = "The public IP addresses of the controlplane server."
+  description = "The public IPv4 addresses of the controlplane server."
 }
 
-output "agents_public_ip" {
+output "agents_public_ipv4" {
   value = [
     for obj in module.agents : obj.ipv4_address
   ]
-  description = "The public IP addresses of the agent server."
+  description = "The public IPv4 addresses of the agent server."
 }
 
-output "load_balancer_public_ip" {
+output "load_balancer_public_ipv4" {
   description = "The public IPv4 address of the Hetzner load balancer"
   value       = data.hcloud_load_balancer.traefik.ipv4
 }