Add Python API functions (convert_nd2_plate, convert_nd2_single_image) for programmatic
use outside Fractal.
Update tests to call the high-level API functions end-to-end.
Docs
Add "Python API" section to README with usage examples.
Chores
Remove _setup_single_image.py and its import: ome-zarr-converters-tools>=0.10.0 now ships
a built-in setup_singleimage handler for SingleImage collections, making the local copy
redundant.
Bump to ome-zarr-converters-tools>=0.10.0,<0.11.0.
Rename nd2_utils.py to _nd2_utils.py to signal private implementation.