Scheduler: Move inventory fields of compute node (continued)

Gerrit topic: https://review.openstack.org/#q,topic:bp/compute-node-inventory,n,z

Addressed by: https://review.openstack.org/279313
    Migrate compute node resource information to Inventory objects

Gerrit topic: https://review.openstack.org/#q,topic:bp/compute-node-inventory-newton,n,z

Addressed by: https://review.openstack.org/279312
    Add Service.get_minimum_version_multi() for multiple binaries

Addressed by: https://review.openstack.org/286931
    Make compute_node_statistics() use new schema

Addressed by: https://review.openstack.org/299526
    Move resource provider staticmethods to proxies

Gerrit topic: https://review.openstack.org/#q,topic:bp/generic-resource-pools,n,z

Addressed by: https://review.openstack.org/300175
    resource-providers: Migrate compute node inventory

Addressed by: https://review.openstack.org/303531
    Drop compute node uuid online migration code

I've marked this complete since https://review.openstack.org/#/c/279313/ is merged and that completes the online data migration for the core resource types (vcpus, memory_mb and local_gb). The spec also mentioned migrating PCI devices and NUMA topology, but in the 2016/04/11 nova scheduler sub-team meeting jaypipes said that those would be deferred to other blueprints. I think we should get the spec updated to reflect that, and I'm not sure what the plan is for those, but we can at least mark this complete. And also note that there is work needed for handling shared storage in the compute node inventory. -- mriedem 2016/04/11

Addressed by: https://review.openstack.org/358348
    rt: remove ComputeNode.create_inventory