add flatcar support for Hetzner (#9618)

contrib/terraform/hetzner/modules/kubernetes-cluster-flatcar/variables.tf

@@ -0,0 +1,60 @@
+
+variable "zone" {
+  type = string
+  default = "fsn1"
+}
+
+variable "prefix" {
+  default = "k8s"
+}
+
+variable "user_flatcar" {
+  type = string
+  default = "core"
+}
+
+variable "machines" {
+  type = map(object({
+    node_type = string
+    size      = string
+    image     = string
+  }))
+}
+
+
+
+variable "ssh_public_keys" {
+  type = list(string)
+}
+
+variable "ssh_private_key_path" {
+  type    = string
+  default = "~/.ssh/id_rsa"
+}
+
+variable "ssh_whitelist" {
+  type = list(string)
+}
+
+variable "api_server_whitelist" {
+  type = list(string)
+}
+
+variable "nodeport_whitelist" {
+  type = list(string)
+}
+
+variable "ingress_whitelist" {
+  type = list(string)
+}
+
+variable "private_network_cidr" {
+  default = "10.0.0.0/16"
+}
+
+variable "private_subnet_cidr" {
+  default = "10.0.10.0/24"
+}
+variable "network_zone" {
+  default = "eu-central"
+}