Import Ironic scheduler filters and host manager

This is an import of the Ironic scheduler changes as of
commit da967d77894be6f23d81fb5cc948f9d13898ba84

implements bp: add-ironic-driver

Co-authored-by: Adam Gandelman <adamg@ubuntu.com>
Co-authored-by: ChangBo Guo(gcb) <eric.guo@easystack.cn>
Co-authored-by: Chris Behrens <cbehrens@codestud.com>
Co-authored-by: Chris Krelle <nobodycam@gmail.com>
Co-authored-by: Devananda van der Veen <devananda.vdv@gmail.com>
Co-authored-by: Fengqian Gao <fengqian.gao@intel.com>
Co-authored-by: Hans Lindgren <hanlind@kth.se>
Co-authored-by: Jenkins <jenkins@review.openstack.org>
Co-authored-by: Lucas Alvares Gomes <lucasagomes@gmail.com>
Co-authored-by: Michael Davies <michael@the-davies.net>
Co-authored-by: Rohan Kanade <openstack@rohankanade.com>
Co-authored-by: Zhongyue Luo <zhongyue.nah@intel.com>

Change-Id: I358d9c0485c5dcf81498871faa9150e3bf167c6b
Merge "Import Ironic scheduler filters and host manager"