Remove isPrivate, isMe, isGroupV1, isGroupV2 from model

ts/util/deprecated.ts

@@ -0,0 +1,11 @@
+// Copyright 2021 Signal Messenger, LLC
+// SPDX-License-Identifier: AGPL-3.0-only
+
+import { getEnvironment, Environment } from '../environment';
+import * as log from '../logging/log';
+
+export function deprecated(message?: string): void {
+  if (getEnvironment() === Environment.Development) {
+    log.error(new Error(`This method is deprecated: ${message}`));
+  }
+}