chore: add sample to main

sample/alpha-from-registry/providers.tf

@@ -0,0 +1,24 @@
+
+terraform {
+  required_providers {
+    stackit = {
+      source  = "registry.terraform.io/stackitcloud/stackit"
+      version = "~> 0.70"
+    }
+    stackitprivatepreview = {
+      source  = "tfregistry.sysops.stackit.rocks/mhenselin/stackitprivatepreview"
+      version = ">=0.1.0"
+    }
+  }
+}
+
+provider "stackit" {
+  default_region           = "eu01"
+  enable_beta_resources    = true
+  service_account_key_path = "../service_account.json"
+}
+
+provider "stackitprivatepreview" {
+  default_region           = "eu01"
+  service_account_key_path = "../service_account.json"
+}