Add obstore to benchmarks

[rly]

With today's Zarr Python release, switch to the new obstore-based backend for 3x faster reading from S3, Google Cloud Storage, and Azure than the default fsspec backend.

https://bsky.app/profile/kylebarron.dev/post/3lnderh3t6k26

This may require Zarr Python v3 though.

• https://zarr.readthedocs.io/en/stable/user-guide/storage.html#object-store
• https://developmentseed.org/obstore/latest/
• https://github.com/maxrjones/zarr-obstore-performance

[rly]

Also relevant is the Earthmover/Icechunk team's recent performance benchmarks and benchmark framework: https://www.linkedin.com/posts/ryan-abernathey_zarr-icechunk-activity-7399134010104528896-L95r

https://earthmover.io/blog/i-o-maxing-tensors-in-the-cloud?trk=comments_comments-list_comment-text