Proposed simplification: remove support for wrapping h5py in LindiH5pyFile

[magland]

Right now LindiH5pyFile can either wrap a zarr object or an h5py object. This leads to a lot of if/else checks throughout the code. For example

        if isinstance(self._group_object, h5py.Group):
            ...
        elif isinstance(self._group_object, zarr.Group):
            ....
        else:
            raise Exception(f"Unhandled type: {type(self._group_object)}")

Initially, my reason for supporting both was a matter of testing/debugging. The h5py case is not used in any of the use cases. This would greatly simplify the codebase.

@rly what do you think?

[magland]

spoke ryan, we're going ahead with this.