Refactor networking and commands

This patch refactors the socket management
to use select, as well as refactor all of the
commands into a COMMAND_ENVELOPE dictionary.

This patch also adds the Dockerfile and
docker-compose.yml files

Dockerfile

@@ -0,0 +1,44 @@
+FROM ubuntu:20.04 as aprsd
+
+
+ENV VERSION=1.0.0
+ENV APRS_USER=aprs
+ENV HOME=/home/aprs
+ENV APRSD=http://github.com/craigerl/aprsd.git
+ENV APRSD_BRANCH="master"
+
+ENV INSTALL=$HOME/install
+ENV DEBIAN_FRONTEND=noninteractive
+RUN apt-get -y update
+RUN apt-get install -y wget gnupg git-core
+RUN apt-get install -y apt-utils pkg-config sudo
+RUN apt-get install -y python3 python3-pip python3-virtualenv
+
+# Setup Timezone
+ENV TZ=US/Eastern
+RUN ln -snf /usr/share/zoneinfo/$TZ /etc/localtime && echo $TZ > /etc/timezone
+RUN apt-get install -y tzdata
+RUN dpkg-reconfigure --frontend noninteractive tzdata
+
+
+RUN addgroup --gid 1000 $APRS_USER
+RUN useradd -m -u 1000 -g 1000 -p $APRS_USER $APRS_USER
+
+USER $APRS_USER
+RUN echo "export PATH=\$PATH:\$HOME/.local/bin" >> $HOME/.bashrc
+VOLUME ["/config"]
+
+WORKDIR $HOME
+RUN mkdir $INSTALL
+# install librtlsdr from source
+RUN git clone -b $APRSD_BRANCH $APRSD $INSTALL/aprsd
+USER root
+RUN cd $INSTALL/aprsd && pip3 install .
+RUN aprsd sample-config > /config/aprsd.yml
+
+# override this to run another configuration
+ENV CONF default
+USER $APRS_USER
+
+ADD build/bin/run.sh $HOME/
+ENTRYPOINT ["/home/aprs/run.sh"]