DRAC hardware introspection

DRAC allows us to interrogate hardware and discover the physical characteristics of the node in a out-of-band fashion. What this blueprint is proposing is to extend the vendor_passthru endpoint of the DRAC driver to expose a method that can be invoked to tell DRAC to find out what are those characteristics (Memory size, CPU count, CPU architeture, Disk size) and populate the node.properties attribute. The method would also find out all the MAC addresses that the node has and create a port for each one of them. Leaving the node in a "ready state" to be deployed.

Right now operators have populate all these informations manually (or script it) but often the information provided by the vendor are not correct, so why should we rely on humans if we the hardware already offer a mean to us to find out it's inventory information? This improves quality!

This blueprint is *not* about node discover, operators would still need to register the node in Ironic with valid credentials first before being able to invoke the method that will introspect the hardware, so the node is known and is registered in Ironic before it can be used.