Added first simple version of CLI script.

src/spatialdata_io/__main__.py

@@ -0,0 +1,29 @@
+import os
+
+import click
+
+import spatialdata_io
+
+
+@click.command()
+@click.argument("input_path", type=click.Path(exists=True))
+@click.argument("output_path", type=click.Path())
+@click.option(
+    "--reader_name",
+    type=click.Choice(
+        ["codex", "cosmx", "curio", "mcmicro", "merscope", "metaspace", "resolve", "steinbock", "visium", "xenium"]
+    ),
+    help="name of the reader to use",
+    required=True,
+)
+def main(input_path, output_path, reader_name):
+    if os.path.exists(output_path):
+        print("Spatialdata object already exists! If you want to recompute it, please delete the existing Zarr store.")
+    else:
+        reader_func = getattr(spatialdata_io, reader_name)
+        sdata = reader_func(input_path)  ## Can only handle mcmicro at the moment. Add logic for other readers!!!
+        sdata.write(output_path)
+
+
+if __name__ == "__main__":
+    main()