We don't need two (and half) templating systems anymore, yay!
I'm keeping the changes minimal, to make the diff manageable. Some enhancements
due to a better templating system might be possible in the future.
For handling of '## ' — see the next commit.
If we have exit on idle, then operations such as "journalctl
--namespace=foo --rotate" should work even if the journal daemon is
currently not running.
(Note that we don't do activation by varlink for the main instance of
journald, I am not sure the deadlocks it might introduce are worth it)