Support saving baremetal compute inspection data

Add the command ``kayobe baremetal introspection data save`` to save the
hardware introspection data gathered by ``kayobe baremetal compute
inspect``. This mirrors the functionality of ``kayobe overcloud
introspection data save``, but for use with the baremetal compute
Ironic, rather than Bifrost.

Change-Id: I654f7d6e923c442a8aa08f536cc2b82c5e5b69d1