Consider supporting demuxed logging from flat binary file

[bruno-f-cruz]

For those still using the current default logging scheme (i.e. IObservable -> MessageWriter) it would be great to provide the demuxed strategy as an option of this tool to process legacy data formats into the current demuxed one.

Since this library already makes use of the Bonsai.Harp library, this should be relatively doable.

Some details might still need to be provided (e.g. device id).