Fix Docker ports & Gunicorn

[Kilo59]

Our current dockerfile was using the tiangolo/uvicorn-gunicorn-fastapi
docker image, but was configured to run as uvicorn directly.

• Updated Dockerfile and docker-compose to work with gunicorn (running uvicorn workers).
• Publish the correct port (80)
• Added invoke docker --build to easily build a docker image.
• Added invoke docker --run to start the container and "publish" the correct port

fixes #269

After building and running the container, the API should be reachable locally at
http://192.168.99.100/

Next steps

• Update docs
• It might be helpful to have another Dockerfile that runs uvicorn directly.
• replace/update the prestart.sh script