fix(publisher): do not publish older app versions

As soon as a newer version of an application is published to etcd,
we should not be publishing any older application versions. This
prevents containers which are orphaned by fleet or systemd to be
exposed by the router.
ref(publisher): change package name to server
Merge pull request #2413 from bacongobbler/1149-etcd-publish

fix(publisher): do not publish older app versions