Newly added NG panels are missing some definitions
in settings.py and settings.rst
NG Domains default is not defined in settings.py
https://review.openstack.org/#/c/387771/
NG Roles default should be described in settings.rst
documentation
https://review.openstack.org/#/c/222825/
Change-Id: I0bddbf2c829467c2c1ea20d96124c66ec46c50b4