Virtualize Native Zarr V2 format

[norlandrhagen]

This PR should soon be merged. We intentionally didn't included reading from V2 Zarr. At some point, we should include this functionality. @sharkinsspatial mentioned some codec changes that might make this a good deal easier.

• Zarr V2 functionality.

[TomNicholas]

There is code in this PR to zarr-python for converting v2 stores to v3 stores that's potentially very relevant.

[norlandrhagen]

Nice find!

[neilSchroeder]

Anyone know if there's an estimated timeline on this? I'd love to be able to use this feature. Happy to assist with contribution where I can if needed.

[TomNicholas]

@neilSchroeder do you want to just have a go at finishing #806? Davis already explained what to do, and I am happy to provide further help. Otherwise this might take a month or two for me to get to perhaps.