Destination aware container names

[tbuehlmann]

I started looking into having role aware container names but that turned out to be quite a big undertaking. So I started with destinations instead to see where it could head.

This PR is a start to have destination aware container names so different destinations of the same service can run on the same server.

This doesn't work right now:

# config/deploy.yml
service: app

# config/deploy.staging.yml
web:
  - 1.1.1.1

# config/deploy.demo.yml
web:
  - 1.1.1.1

… as both docker containers would have the same name app-<version> on 1.1.1.1. The PR adds - if present - the destination as part of the container name, ending up as app-staging-<version> and app-demo-<version>.

I started with Mrsk::Commands::App and Healthcheck and before changing all of the other commands: Is this the way we want it to be? It'll include some if conditions on whether or not MRSK.destination (or config.destination) is truthy or not.

Another approach could be to default the destination to "production" if it's missing. This would probably be simpler but is more chatty in regards to the container names (if no destination is used it would be app-production-<versions> instead of app-<version>).