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.
This is great!  We'll also have to implement it in the other Dockerfiles.  I'll create an issue.