Add support for naming containers when deploying them

 When running several containers based on a single image on one host, it's useful to be able to name them.

For instance, when running four containers doing a processing job, it's nicer to have them named `backend1`, `backend2`, `backend3` and `backend4` instead of just having generated names.

Another example are images that can perform different tasks depending on configuration (like environment variables), so the containers could be named `backend-encoding`, `backend-multiplexing`, `backend-decoding` and so on.
Do we need the whole hash? It would be nice to use like the first 7 digits (a la git) instead of the whole thing.