MFC r325834,r325997,326502: Move sys/boot to stand/

This is effectively a direct commit to stable/11, due to differences between
stable/11 and head. Changes to DTS in sys/boot/fdt/dts were often
accompanied by kernel changes. Many of these were also risc-v updates that
likely had many more dependencies to MFC.

Because of this, sys/boot/fdt/dts remains as-is while everything else in
sys/boot relocates to stand/.

r325834: Move sys/boot to stand. Fix all references to new location

r325997: Remove empty directories.

r326502: Document the sys/boot -> stand move in hier.7 and the top-level README.

MFC r318294:
Correct the URL to instructions for updating system sources.

PR: 219303
Sponsored by: The FreeBSD Foundation

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

README: remove nonexistent 'games' directory.

Games were moved to usr.bin in r288485.

(todo: add/describe 'targets' directory)

README: changes and fixups
Two orthogonal goals:
- try to make README look a little nicer on phabricator by using
Remarkup syntax for commands (using `` instead of using a closing ')
- try to make README look a little nicer on github.

- Don't encourage `make world` when the handbook specifies otherwise
- Change language around documentation to be a bit clearer

MFC After: 2 weeks

README:
- the reference to 'ancient' LINT file was added in 2000 [r64047 | alex
| 2000-07-31]. Remove the reference entirely now.
- add the tests directory

Add the cddl/ directory.

Simply running ``make world'' will bomb unless you dig up the
undocumented HISTORICAL_MAKE_WORLD variable and set it. Note it
here so the blow up will not really be a surprise to people who
read.

Link the buildingworld chapter of our handbook in the README
while I'm here.

Add a note explaining what the rescue/ directory is for.

PR: docs/93990
Submitted by: Ulf Lilleengen
MFC after: 3 days

KerberosIV de-orbit burn continues. Disconnect from "make world".

Fix broken handbook links.

Submitted by: "Dipl.Phys. Andreas Hiltenkamp" <hiltenkamp@web.de>

Spell "FreeBSD" correctly.

`buildworld' is no longer a strict prerequisite for `buildkernel'
as of Makefile.inc1,v 1.184.

Fix kernel configuration files path to look MI.

Mention src/kerberos5.

Slightly improve the description of "crypto". "DES" is a subset of
what we have in secure/.

secure/ may be exported now.

Point out, that build/installkernel need a built world and that more
information can be found in the handbook.

Requested by: sheldonh
Reviewed by: sheldonh

Reflect reality:
- Make world doesn't build the modules any more.
- Mention the buildkernel/installkernel targets as common used targets.
- LINT has gone, NOTES is new but cannot be built. It is a pure reference
file. However, I still mentioned LINT but pointed out the difference
between the ancient LINT and the new NOTES. This should avoid confusion.
- crypto/ subdir isn't export controlled any more.

$Id$ -> $FreeBSD$

No more src/lkm dir...

Correct the facts. The kerberosIV/ directory is not export restricted.

Re-alphabetize and update the subdir descriptions.

PR: 7116

Note that /etc is not installed by world target either.

Revert $FreeBSD$ to $Id$

Make the long-awaited change from $Id$ to $FreeBSD$

This will make a number of things easier in the future, as well as (finally!)
avoiding the Id-smashing problem which has plagued developers for so long.

Boy, I'm glad we're not using sup anymore. This update would have been
insane otherwise.

Typo (maybe), config(1) -> config(8).

Bring back the README, this time attempting to be a little more
informative about what the user is seeing here.