Add Terraform test for backend resource setup

Introduces a test configuration and supporting Terraform code to provision Azure resources for backend state storage. This includes a resource group, storage account, and storage container, enabling automated validation of backend setup for GitHub runners.

Author: potatoqualitee

gh-runners/backend-setup.tftest.hcl

@@ -0,0 +1,7 @@
+run "setup_backend_resources" {
+  command = apply
+
+  module {
+    source = "./tests/backend-setup"
+  }
+}

gh-runners/tests/backend-setup/main.tf

@@ -0,0 +1,33 @@
+terraform {
+  required_version = ">= 1.0"
+
+  required_providers {
+    azurerm = {
+      source  = "hashicorp/azurerm"
+      version = "~> 3.0"
+    }
+  }
+}
+
+provider "azurerm" {
+  features {}
+}
+
+resource "azurerm_resource_group" "tfstate" {
+  name     = "dbatools-ci-runners"
+  location = "East US"
+}
+
+resource "azurerm_storage_account" "tfstate" {
+  name                     = "dbatoolstfstate"
+  resource_group_name      = azurerm_resource_group.tfstate.name
+  location                 = azurerm_resource_group.tfstate.location
+  account_tier             = "Standard"
+  account_replication_type = "LRS"
+}
+
+resource "azurerm_storage_container" "tfstate" {
+  name                  = "tfstate"
+  storage_account_name  = azurerm_storage_account.tfstate.name
+  container_access_type = "private"
+}