Support streaming upload of Directories

[AuHau]

Currently, it is possible to upload in streaming way file with the uploadFiles() method when Readable is passed. This is possible only in NodeJs at the moment as browsers currently does not support streaming requests. This will hopefully change soon as for example, Chrome has already experimental support for this (https://web.dev/fetch-upload-streaming/).

But... The current implementation of upload of directories relies on the creation of Tar before the upload. This is done all in the memory, so if for example uploading a large directory to Swarm, then everything needs to be loaded into memory, which might lead to Out of Memory errors for Nodejs. It is possible to create Tar in streaming way with tar-stream. We should revisit this to add support for the streaming of directories.