Missing metadata in Multiscale generation

[mzouink]

When generating a dataset we add s0 to support mutiscale but we are missing metadata

cellmap-flow/cellmap_flow/blockwise/blockwise_processor.py

Lines 123 to 132 in adbd54f

	array = prepare_ds(
	DirectoryStore(self.output_path / channel / "s0"),
	output_shape,
	dtype=self.dtype,
	chunk_shape=self.block_shape,
	voxel_size=self.output_voxel_size,
	axis_names=["z", "y", "x"],
	units=["nm", "nm", "nm"],
	offset=(0, 0, 0),
	)

Can get inspired by
https://github.com/janelia-cellmap/cellmap-analyze/blob/a84d249f9689c74d8d509de359c878d85b6704ba/src/cellmap_analyze/util/zarr_util.py#L43-L70

[mzouink]

@yuriyzubov do you have time to help with this ?

[yuriyzubov]

#66