Treat devices (including PCI) as generic resources

We have PCI passthrough. We would like to make the same paradigm work for any device. So one half of this work is to make it possible to whitelist, alias, specify, claim, and attach all devices the same way PCI passthrough devices are supported today. The second half of this work (which may be subsumed under one of the resource providers blueprints) is to move device inventorying and claiming into the resource provider framework. I should be able to have my resource provider say, "I have X devices of type Y with traits A, B, and C" and have my claim grab one and feed it to the compute driver, which does the work of assigning it to the VM.