add hetzner module (#1)

Create a module to provision VMs in hcloud

Reviewed-on: #1

modules/hetzner_server/variables.tf

@@ -0,0 +1,45 @@
+variable "project_name" {
+  type        = string
+  description = "Project / host name"
+}
+
+variable "ssh_public_key" {
+  type        = string
+  description = "Public SSH key to manage the host"
+}
+
+variable "hcloud_server_type" {
+  type        = string
+  description = "Hetzner server type (e.g. cx22)"
+}
+
+variable "hcloud_image" {
+  type        = string
+  description = "OS image to boot (e.g. debian-13)"
+}
+
+variable "hcloud_location" {
+  type        = string
+  description = "Hetzner location (fsn1, nbg1, hel1, ash1)"
+  validation {
+    condition     = contains(["fsn1", "nbg1", "hel1", "ash1"], var.hcloud_location)
+    error_message = "location must be one of fsn1, nbg1, hel1, ash1"
+  }
+}
+
+variable "init_user_data" {
+  type        = string
+  description = "Pre-rendered cloud-init user data (optional)"
+  default     = null
+}
+
+variable "firewall_rules" {
+  type = list(object({
+    direction  = string
+    protocol   = string
+    port       = string
+    source_ips = list(string)
+  }))
+  description = "Firewall rules applied to the host"
+  default = []
+}