Get rid of the TODO in the code and prepare for more management
interfaces supporting detect_vendor(). Vendor detecting now runs
during transition to manageable and on power state sync (essentially
same as before but for all drivers not only IPMI).
Update the IPMI implementation to no longer hide exceptions since
they're not handled on the upper level. Simplify the regex and fix
the docstring.
Add the Redfish implementation as a foundation for future
vendor-specific changes.
Change-Id: Ie521cf2295613dde5842cbf9a053540a40be4b9c
(cherry picked from commit 121b3348c8)
4df73e47e1