Merge r263497: fix ipfw + VIMAGE sysctls.

PR:		kern/187665
MFC r263471:
Initialize vm_map_entry member wiring_thread on the map entry creation.
MFC r263289: Update NetBSD Foundation copyrights to 2-clause BSD

  The NetBSD Foundation states "Third parties are encouraged to change the
  license on any files which have a 4-clause license contributed to the
  NetBSD Foundation to a 2-clause license."

  This change removes clauses 3 and 4 from copyright / license blocks that
  list The NetBSD Foundation as the only copyright holder.

Sponsored by:	The FreeBSD Foundation
MFC r261765:

Improve error reporting.

Sponsored by:	The FreeBSD Foundation
MFC r261766:

Make ctld error out on invalid characters in ctl.conf.

Sponsored by:	The FreeBSD Foundation
MFC r261767:

Show proper configuration file line numbers in error messages.

Sponsored by:	The FreeBSD Foundation
MFC r261768:

Make the debug messages during ctld(8) shutdown less confusing.

Sponsored by:	The FreeBSD Foundation
MFC r261749:

Refactor.

Sponsored by:	The FreeBSD Foundation
MFC r261750:

Improve check for duplicated paths.  It shows the warning twice for every
path (once for each duplicate found), but it should do for now.

Sponsored by:	The FreeBSD Foundation
MFC r261753:

Daemonize after applying configuration, not before, so that
any problems - including "daemon already running" - are visible
on the terminal and not just in logs.

Sponsored by:	The FreeBSD Foundation
MFC r261754:

Implement initiator-name and initiator-portal restrictions.

Sponsored by:	The FreeBSD Foundation
MFC r261755:

Make function ordering slightly more logical; no functional changes.

Sponsored by:	The FreeBSD Foundation
MFC r261756:

Yacc cleanup; no functional changes.

Sponsored by:	The FreeBSD Foundation
MFC r261757:

Rename a variable, no functional changes.

Sponsored by:	The FreeBSD Foundation
MFC r261758:

Add auth-type.

Sponsored by:	The FreeBSD Foundation
MFC r261759:

Make it possible to redefine portal-group "default".

Sponsored by:	The FreeBSD Foundation
MFC r261760:

Add a new auth-group "default", defaulting to deny, and make it possible
to redefine it.  From now on, assigning auth-group to a target is no longer
mandatory.

Sponsored by:	The FreeBSD Foundation
MFC r261761:

Update manual page to match recent auth-group "default" changes.

Sponsored by:	The FreeBSD Foundation
MFC r261762:

Use "default" as default discovery-auth-group, instead of "no-access".
It doesn't change visible behaviour, as previously auth-group "default"
wasn't redefinable, so by default access was always denied.

Sponsored by:	The FreeBSD Foundation
MFC r261763:

Use new auth-type "deny" instead of using "chap" with no chap entries;
it's cleaner this way, and gives better feedback to the user.

Sponsored by:	The FreeBSD Foundation