Add uploading to internal cloud storage

Summary:
Design doc: https://docs.google.com/document/d/1HLCFl46RfqG0o1mSt8SWrwf_HMfOCRg_oENioc1rkvQ/edit#

We'll use it in the subsequent diff to automatically upload a universal export

Reviewed By: passy

Differential Revision: D40585810

fbshipit-source-id: 5b409d716c2ead040865130d379d4f593cb68483

desktop/flipper-server-core/src/fb-stubs/jf.tsx

@@ -0,0 +1,17 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @format
+ */
+
+/**
+ * Upload a file at path to a temporary cloud storage
+ *
+ * @returns Download URL
+ */
+export const jfUpload = async (_path: string): Promise<string> => {
+  throw new Error('jf upload is not implemented');
+};