Add stubbed support for decom for testing

This adds support for the new decom functions added to the decom extension and the updates hardware manager: https://review.openstack.org/#/c/104379/. Functions are stubbed out to log for first round of testing and will be implemented incrementally.
If you're going to stub out everything, probably want to stub out the update bios settings stuff too.

For now just implement it with the decom settings. We'll add customer settings once that's working and tested.