Add zarr3 streaming

[normanrz]

Detailed Description

Webknossos can already read zarr3 data. It would be great to also stream data out. However, the OME-Zarr metadata for zarr3 is not finalized yet. There is a proposal that we can implement right now: ome/ngff#242 (with the version tag "0.5-dev2")
The first iteration doesn't need to have sharding, so it will basically just need some new routes for the metadata. We should put this under an experimental route, e.g. /data/zarr_experimental/scalable_minds/l4_sample/color/