Added docker_container action :create (wrapper to 'docker create').

This simple PR adds a new :create action to the docker_container LWRP.

The action wraps the `docker create` command (introduced with docker 1.3.0) which is the same as `docker run` except that it does not start the created container. The `docker create` command supports the same args as the `docker run` command except for a few (detach, security-opt, rm and sig-proxy if I believe the manual page).