Remove $FreeBSD$: one-line sh pattern

Remove /^\s*#[#!]?\s*\$FreeBSD\$.*$\n/

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

Rewrite usermgmt -- hooking it into the scripting system with dispatch
commands addUser, deleteUser, and editUser. Getting rid of the awkward-
to-use `userinput' bolt-on which Ron and I talked about rewriting.

Rewrite groupmgmt -- hooking it into the scripting system with dispatch
commands groupAdd, groupDelete, and groupEdit. Getting rid of the awkward-
to-use `groupinput' bolt-on which Ron and I talked about rewriting.

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

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

Import bsdconfig(8) as a replacement for the post-install abilities of
deprecated sysinstall(8). NOTE: WITH_BSDCONFIG is currently required.

Submitted by: Devin Teske (dteske), Ron McDowell <rcm@fuzzwad.org>
Reviewed by: Ron McDowell <rcm@fuzzwad.org>
Approved by: Ed Maste (emaste)