registering zarr files

[gdkrmr]

I want to register Zarr files. The issue is that Zarr files are not files but directories that contain certain JSON. Is it possible to to this in FileIO.jl? JuliaDataCubes/YAXArrays.jl#131

[johnnychen94]

I don't think FileIO supports directory because it internally uses open(...) do io here and there. Do we have a well-defined read behavior for a directory, I'm not sure?

Perhaps a good approach is to add Zarr driver in DataSets.jl