Separate mysql into its own container

* creates dockerfiles for mysql server/data containers
* moves files around so that each container has its own subfolder/Dockerfile
* quick instructions in README
* tweaks dw server to be able to use the linked mysql container  (a proper for-prod setup across multiple servers will need to use the [Ambassador Pattern](http://docs.docker.io/use/ambassador_pattern_linking/#ambassador-pattern-linking))

Also, hey root with no password ;)  *handwave*