Blogpost idea: how to generate multiscale image arrays

This PR is currently in progress, but could be merged soon (for some loose value of "soon", I don't have a good idea of when) https://github.com/ome/ome-zarr-py/pull/192

When it is done, I think it might be nice to have a blogpost about how to generate a multiscale image array and save it to disk, etc.

This is something that surprisingly doesn't seem to have a single, obvious, best way to do it (see discussion https://github.com/ome/ome-zarr-py/issues/215). So when there is a convenience function available, it would be good to highlight that with a blogpost.

Jacob, feel free to nudge me in a few months about this, if you like. (That may or may not *work*, I can't say for sure I'll be available to do more about it then, but it's worth a try)

Start by reviewing PR #192 and the discussion in issue #215 to understand the eventual convenience function and the recommended workflow. The work is done when a blog post clearly explains how to generate a multiscale image array and save it to disk using the finalized approach.

Written by the indexing model from the issue text.