this patch changes the entrypoint and commands to be in line
with how Docker defines their usage. this allows the admin using
this container to specify which command to run in the
docker-compose.yml if they want to run something other than the
aprsd server command.
This now allows to easily run webchat as a container :)!
This patch starts the work to replace flask-socketio with
python-socketio so that uwsgi can be used instead of gunicorn.
uwsgi can support websockets.
Have to rework webchat command next
This patch updates the main Dockerfile container build to use
the python:3.8-slim base image and installs aprsd from pypi.
This also results in a much smaller image.
Also added support for multiarchitecture builds so the same Dockerfile
builds for raspberry pi and linux/amd64
