Expose node capabilities to COE engine

It would be nice to expose the node capabilities as labels in docker (or kubelet) so that they can be used for container scheduling.

Some values come from the nova metadata, others could be queried directly on the nodes.

Nova is working on a library to keep track of these items:
https://github.com/jaypipes/os-traits

and on exposing them via the Nova API, which is also an option.