Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

META MODE: These need object directories to handle staging.

Sponsored by: EMC / Isilon Storage Division

Follow-up to r255036; remove beforeinstall directives from bsdconfig(8)
Makefile's, fixing concurrent installworld (`make -j17 installworld').

Thanks to: delphij, emaste
Reviewed by: delphij
MFC after: 3 days
X-MFC-to: stable/10, stable/9

Add the beginnings of the old networking services functionality of
sysinstall(8). The UI for this will come later while this exposes the
functionality to the scripted interface. Tested successfully to first
install the pcnfsd package from the `Latest' repository, and second to
configure mountd_flags="-n" in rc.conf(5).

Move major includes into /usr/share/bsdconfig for easy external access.

Reviewed by: adrian (co-mentor)
Approved by: adrian (co-mentor)