Can't import the data module thus can't use the default d3 parameters outside the main project directory

[MarshallYan]

Need to put init.py in the data directory.

[MarshallYan]

When modelforge is install in editable mode (-e), modules in the package will be imported from the development directory. Since our d3 parameters are stored as a pt file under the development directory, training with nvalchemiops works. It will not work without the -e flag since the pt file is not copied to the installation directory (e.g., ./miniforge3/envs/modelforge/lib/python3.12/site-packages/modelforge/data/dftd3_parameters).

Not sure how this was handled in the dataset module where all the yaml files are in the installation as well.