Make Stream() an async iterator

[Fishrock123]

I think Stream() would be a good place for this, what does everyone else think?

We should also be sure to handle cases such as nodejs/node#28194

[Raynos]

Stream is a utility for connecting multiple bob streams together. It seems to be used like pipeline()

For async iterator use case we can just export a function or class to make the iterator.

Doing this in stream() means you cannot really create an iterator for a single source or duplex cleanly