Feat/production ready build

[pharr117]

This PR adds a bit of code organization and features to do the following:

1. Add argparse usage to define three app subcommands: debug, reader, writer
2. Add different app run modes for the three subcommands:
   • python app.py debug: runs the application the same as it has been running
   • python app.py reader: runs the Flask application only with a FileSystem cache that Flask reads data from
   • python app.py writer: runs just the data update cycle with a FileSystem cache that the process writes to
3. Move Flask app building into Factory functions, which will provide gunicorn with a Flask app to get

This also adds a docker-compose.yaml file with:

1. Two services, one for a gunicorn build running the Flask reader process and one for the data writer
2. A shared volume that the cache location is pointing to, allowing the systems to use the same FS cache for reading and writing

[pharr117]

Closing this for now, we are exploring a more robust data store implementation.