Create Dockerfile for Kronos

Docker has 3 kronos services, one for all, one for readonly, one for collector. When docker is run, all three are started. Three ports are mapped. The log directory is mapped to `/var/log/kronos`. Settings file at `/etc/kronos/settings.py` is mapped into the docker.
if we do /etc/kronos/:/etc/kronos, what's the plan for running multiple instances in production?  i guess we can have a different production mapping.