Implement to_zarr with ngff-zarr

[thewtex]

Refactor the implementation of to_zarr to use to_ngff_zarr in ngff-zarr. The will provide a more robust, scalable, efficient, and more complete OME-Zarr export. Support OME-Zarr v0.5, sharding, etc.

[will-moore]

I wonder if to_zarr() should be included in the examples on the README, as it states "Store as an Open Microscopy Environment-Next Generation File Format (OME-NGFF) / netCDF Zarr store." without saying how you do that?

I was just coming here from https://ngff.openmicroscopy.org/tools/ to compare writing OME-zarr between various tools, so that was the example I was looking for.

[thewtex]

@will-moore yes, good idea.

To clarify, "OME-NGFF" was written before there was more naming clarification in the community -- it should be "OME-Zarr".

The OME-Zarr here is written in a way that it is also a valid, useful netCDF Zarr. I brought the requirements for this in ome/ngff.