A few suggestions to improve the quality of the repo

[Tobias-Fischer]

Hi @jasonlyik,

I finally got around looking at this :).

A few suggestions:

• Improve the README with a "Get started" or similar that contains installation instructions + most common commands to run; also in the README refer to the other Markdown documents
• Add a requirements.txt / pyproject.toml / pixi.toml file to easily install dependencies
• Add a LICENSE, and add license information in all code files
• Move the ASC.md / QUBO.md in the relevant subdirectories as "README.md" files
• In download_dcase_dataset.py:
  • Do we really need the MKDIR_MODE? Could cause trouble on Windows I imagine ..
  • Why not just call download_dcase_audio_data() in the __main__()? Feels like duplicated handling of the default path.
• In dcase_audio_scene_classification.py: Why return self in def to()?

Otherwise looks good & exciting :)