Provide explicit guidance/expectations for zarr uploads

[aaronkanzer]

Zarr uploads still remain in Draft mode, as they are yet to be versioned.

Our handbook does not provide documentation for "what to expect" for Zarr uploads in the DANDI ecosystem. (e.g. https://github.com/dandi/handbook/blob/master/docs/13_upload.md does not contain any reference)

The goal of this Issue is to capture follow-up work to communicate the Zarr workflow correctly in this handbook, dandi-cli and dandi-archive

Relates to dandi/dandi-archive#1811

[kabilar]

Thank you @aaronkanzer. I will update the handbook to describe the user flow for Dandisets with Zarr assets.