Add initial Terraform module structure for firewall and network

- Created main.tf, output.tf, and variables.tf for the firewall module.
- Created main.tf, output.tf, and variables.tf for the network module.
- Added provider configuration for Hetzner Cloud and NetBox in provider.tf.
- Defined sensitive variables for Hetzner API token, NetBox URL, and NetBox API token in variables.tf.

terraform/provider.tf

@@ -0,0 +1,21 @@
+terraform {
+  required_providers {
+    hcloud = {
+      source = "hetznercloud/hcloud"
+      version = "1.57.0"
+    }
+    netbox = {
+      source = "e-breuninger/netbox"
+      version = "5.0.0"
+    }
+  }
+}
+
+provider "hcloud" {
+  token = var.hetzner_api_token
+}
+
+provider "netbox" {
+  server_url = var.netbox_url
+  api_token  = var.netbox_api_token
+}