ironic/baremetal: add validation of host manager/state APIs

Add tests to ensure the ironic & baremetal HostManager and
HostState sub-classes comply with the API contract defined
in their parent class.

Related-bug: #1369151
Change-Id: Ic2cf17c59c06fe2222db4bc5ea0e68f87c4399e9
Merge "ironic/baremetal: add validation of host manager/state APIs"