Removes docimpactgroup: openstack-manuals for select Oslo repos

- Only config items contain doc impact for openstack-manuals.
- Otherwise Oslo is for contributor devs and we do not
track those in the openstack-manuals Launchpad project.

Change-Id: I42f8b00c8593018b61835fcdab5986336552ce67
Merge "Removes docimpactgroup: openstack-manuals for select Oslo repos"