Add init syntax for scripts directory

[j316chuck]

Add init syntax for scripts directory.

@bmosaicml was running into issues importing the scripts.data_prep.convert_dataset_hf file in the test_training.py test but import scripts was working. This PR should fix these import errors.

_______________________________ ERROR collecting tests/test_training.py ________________________________
ImportError while importing test module '/Users/jeremy.dohmann/LLMWork/llm-foundry/tests/test_training.py'.
Hint: make sure your test modules/packages have valid Python names.
Traceback:
/Library/Developer/CommandLineTools/Library/Frameworks/Python3.framework/Versions/3.9/lib/python3.9/importlib/__init__.py:127: in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
tests/test_training.py:17: in <module>
    from scripts.data_prep.convert_dataset_hf import main as main_hf  # noqa: E402
E   ModuleNotFoundError: No module named 'scripts.data_prep'

[dakinggg]

I'd prefer we not do this. Anything that needs to be imported should probably be part of the llmfoundry package properly, and for testing scripts specifically we can just append to the path in the test file so the script main can be imported.

[j316chuck]

Agreed closed. Strange that Jeremy saw this bug earlier.

[dakinggg]

I resolved this with Jeremey earlier. It was an issue specific to his python setup.