Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

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

MFC: r240336:
Simply things so that "#REQUIRE: FILESYSTEMS" means the file
systems are fully "ready to go".

'FILESYSTEMS' states: "This is a dummy dependency, for services which
require file systems to be mounted before starting." However, we have
'var' which is was run after 'FILESYSTEMS' and can mount /var if it
already isn't mounted. Furthermore, several scripts cannot use /var
until 'cleanvar' has done its thing. Thus "FILESYSTEMS" hasn't really
meant all critical file systems are fully usable.

MFC r230099:

Change rcvar= assignments to the literal values set_rcvar
would have returned. This will slightly reduce boot time,
and help in diff reduction to HEAD.

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

Add the shutdown KEYWORD to those scripts that start persistent services
to allow them to do a "clean" shutdown.

I purposely avoided making changes to network-related stuff since the
system shutting down is pretty conclusive, and there may be complicated
dependencies on the network that I would rather not try to unravel.

I also skipped kerberos-related stuff for the reasons above, and
because I have no way to test it.

As previously discussed, add the svn:executable property to all scripts

Add an rc.d script for stand-alone ftpd.

Document the script's controls on the rc.conf(5)
manpage and touch its Dd.

PR: conf/90893
MFC after: 5 days