add ENV var for container service name with version

[moomerman]

I want to know what the unique service + version name is inside the docker container and I can't find a way of getting that information at present.

I propose a MRSK_CONTAINER_NAME (name tbd) ENV var is set when running the container so that it can be read by the running service inside the container.

Happy to implement if it is desired.

[dhh]

Sounds good to me 👍