Make it possible to use service name for all actions

[mdanielolsson]

Currently it's expecting only the service name when creating secrets, but all other actions require the full name of the secret. On create it will append the service name with container name to use as secret name.
It makes sense to be able to use only service name for all actions - assume the default container unless --container is set.

First version of this update should preferably support both the current way and the suggested way.