Update resman modules (#475)

* Make logging sinks in different resources use the same API

* Split resman modules in multiple files. Add nullables where applicable

modules/folder/iam.tf

@@ -0,0 +1,40 @@
+/**
+ * Copyright 2022 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+# tfdoc:file:description IAM bindings, roles and audit logging resources.
+
+locals {
+  group_iam_roles = distinct(flatten(values(var.group_iam)))
+  group_iam = {
+    for r in local.group_iam_roles : r => [
+      for k, v in var.group_iam : "group:${k}" if try(index(v, r), null) != null
+    ]
+  }
+  iam = {
+    for role in distinct(concat(keys(var.iam), keys(local.group_iam))) :
+    role => concat(
+      try(var.iam[role], []),
+      try(local.group_iam[role], [])
+    )
+  }
+}
+
+resource "google_folder_iam_binding" "authoritative" {
+  for_each = local.iam
+  folder   = local.folder.name
+  role     = each.key
+  members  = each.value
+}