[RFE] Exposing Hardware Capabilities

Hardware can have a wide range of capabiltiies and potential configuration. Ironic should expose these capabilities in a declarative way, and allow deployers to configure custom Nova flavors that map to specific types of hardware or hardware configurations. Ironic should then ensure these assertions about the hardware are made valid during the deploy process. For instance, a machine booted with capabilities ["vt_on", "turbo_mode_off"] would have Ironic properly configure those BIOS settings before deploying an image onto the node.