Open Stack

I have a PoC patch up in devstack[0] to start using the openstack-server 
client. It passed the basic devstack test and looking through the logs 
you can see that openstack calls are now completing in fractions of a 
second as opposed to 2.5 to 3, so I think it's working as intended.

That said, it needs quite a bit of refinement. For example, I think we 
should disable this on any OSC patches. I also suspect it will fall over 
for any projects that use an OSC plugin since the server is started 
before any plugins are installed. This could probably be worked around 
by restarting the service after a project is installed, but it's 
something that needs to be dealt with.

Before I start taking a serious look at those things, do we want to 
pursue this? It does add some potential complexity to debugging if a 
client call fails or if the server crashes. I'm not sure I can quantify 
the risk there though since it's always Just Worked(tm) for me.

-Ben

0: https://review.opendev.org/676016