Proxy nova baremetal commands to Ironic

This patch will proxy baremetal-node-list and baremetal-node-show
commands to Ironic. All other commands will raise an error if the
compute_driver is set to Ironic, otherwise the api will act as
expected.

Co-authored-by: Lucas Alvares Gomes <lucasagomes@gmail.com>
Change-Id: Id9209d1d34a725750342434fbde1ff5681ff06b8
Merge "Proxy nova baremetal commands to Ironic"