[Docs] document file and directory streaming

[samhita-alla]

Description

the flytefile and flytedirectory streaming feature is currently experimental. nonetheless, it's important that we document it in the user guide: https://docs.flyte.org/projects/cookbook/en/latest/auto_examples/data_types_and_io/file.html and https://docs.flyte.org/projects/cookbook/en/latest/auto_examples/data_types_and_io/folder.html pages.

streaming PR: https://github.com/flyteorg/flytekit/pull/1512 additional details can be found in the release notes.

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[neverett]

Added to planned work for docs team.

[kumare3]

@neverett did we end up documenting this?

[DenChenn]

I think I can work on this one~

[DenChenn]

@davidmirror-ops done ✅

[davidmirror-ops]

Completed in #5879