service_account_config for Cloud Run v2

Additional changes:
* align vpc-connector interface to Cloud Functions
* split managed and unmanaged resources into separate files, this makes
  easier to introduce further changes
* add support for contexts
* move `vpc_connector` variable to variables.tf for Cloud Functions
* remove `create` from `vpc_connector` in Cloud Functions as it was
  sharing the meaning with `vpc_connector_create`

modules/cloud-run-v2/recipes/cloudsql-iam-auth-proxy/README.md

@@ -89,13 +89,16 @@ module "database_run" {
       }
     }
   }
-  service_account     = module.run-sa.email
-  deletion_protection = false
+  service_account_config = {
+    create = false
+    email  = module.run-sa.email
+  }
   volumes = {
     custom_cloudsql = {
       empty_dir_size = "128k"
     }
   }
+  deletion_protection = false
 }
 # tftest inventory=recipe-cloudsql-iam-auth-proxy.yaml e2e
 ```