FR: Firebase Storage `putFile` should support packaged files like .numbers or .pages

### Feature proposal

* Firebase Component: Storage

Currently `putFile` only support single file like `.txt` or `.png`. However there are several types of packaged files that appear like a single file but in fact is a directory, for example `.numbers` or `.pages`. `putFile` currently unable to upload the packaged files, as reproducible in https://github.com/firebase/firebase-ios-sdk/issues/5720

It would be great if `putFile` can handle upload all types of files, so client doesn't need to check the type of files and handle packaged file differently.