This change adds set_provision_state and wait_for_provision_state
to openstack.baremetal.v1.Node, as well as set_node_provision_state
to the bare metal Proxy. Also adds wait_for_nodes_provision_state,
which is similar to Node.wait_for_provision_state but handles several
nodes at the same time, which is important for bulk operations.
The cloud's node_set_provision_state was updated to use the new calls.
As a nice side effect, it now supports all provision states and actions
up to the Queens release, as well as does proper microversioning.
Some documentation was written for the bare metal proxy.
Change-Id: I22a76c3623f4dd2cca0b2103cbd8b853d5cebb71
5e4420763a