Add a docker compose configuration and mailman-web

This commit adds a lot of new code including the mailman's web
frontend. It includes a configuration file which can later be
configured to run required configs.

Also, the docker-compose file spins off the containers, sets up
appropriate volumes and links.

core/Dockerfile

@@ -15,4 +15,6 @@ ADD assets/pidproxy.py /opt/pidproxy.py
 # Change the working directory.
 WORKDIR /opt/mailman
 
+EXPOSE 8001
+
 CMD /opt/run.sh