1. Create a new API endpoint and client spin to wait for GIE containers to
become ready. IEs are not required to use it, but usage does require
a slight change to their `load_notebook()` functions.
2. Add a Docker swarm manager daemon that runs automatically
to add nodes when services are waiting, clean up exited services, and
remove idle nodes. Shuts down automatically when there's nothing to
do.
The format of the GIE proxy session database has changed, if GIEs are
running when you restart Galaxy, they will be interrupted. If you run
the GIE proxy separate from Galaxy, you should restart it after
upgrading.