Allow custom hostname for docker containers in native services

Instead of the default random docker container hostname, we could set a more user-friendly hostname for the container. The default could be a hostname based on the container ID, with an option for the AM to provide a different hostname. In the case of the native services AM, we could provide the hostname that would be created by the registry DNS server. Regardless of whether or not registry DNS is enabled, this would be a more useful hostname for the docker container.