Docker base container for main Consul on Ubuntu Trusty Tahr.
Meant to be cluster controller, single by default but can be scaled up by changing environment variable.
Exposes volume for Consul configuration files in /opt/consul/conf
Default configuration is provided in 50-defaults.json but can be overriden, just mount a directory with *.json files there and Consul will load them.
Exposes all Consul ports for all transports as well as WEB UI, dns port is 53.