Rename present to running, add new present state

The new present state just makes sure that a container exists, not that
it's running. It's very useful for data volumes. This also changes the old
present, now running (default) state to only create the container if
it's not found.

See also discussion on mailinglist:
https://groups.google.com/forum/#!topic/ansible-devel/jB84gdhPzLQ

This closes #6395