Jp2 writer: fix single-slice reconstruction

About

The following part is problematic:

        if data.ndim == 3 and data.shape[0] == 1:
            # case we will have a single file as output
            data_url = DataUrl(
                file_path=path.dirname(self.fname),
                data_path=self.fname,
                scheme=JP2KVolume.DEFAULT_DATA_SCHEME,
            )
            metadata_url = DataUrl(
                file_path=path.dirname(self.fname),
                data_path=f"{path.dirname(self.fname)}/{path.basename(self.fname)}_info.txt",
                scheme=JP2KVolume.DEFAULT_METADATA_SCHEME,
            )
            volume_basename = None
            folder = None
            extension = None

because it removes the _0123 suffix.

To do

• Fix writer.JP2Writer
• End-to-end reconstruction test