sys: Remove $FreeBSD$: two-line .h pattern

Remove /^\s*\*\n \*\s+\$FreeBSD\$$\n/

Remove #warning since it breaks libsysdecode

Add warning to sys/joystick.h announcing its planned demise.

Revert r339563.

I held the mistaken belief this was completely unused. While the
driver is unused and likely not relevant for a long time,
sys/joystick.h lives on in maybe half a dozen ports, even though
hardware to use it hasn't been widely used in maybe 15 years.

Remove joy(4) driver.

This driver was marked as gone in 12. We're at 13 now. Remove it.
Data from nycbug's dmesg cache shows only one potential user,
suggesting it never was used much.

RelNotes: yes
Differential Revision: https://reviews.freebsd.org/D17629

sys/sys: further adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

A new jail(8) with a configuration file, to replace the work currently done
by /etc/rc.d/jail.

- Import the HEAD csup code which is the basis for the cvsmode work.

Comment typo.

PR: kern/75923
Submitted by: Matthew D. Fuller <fullermd@over-yonder.net>

Fix typo in the BSD copyright: s/withough/without/

Spotted and suggested by: des
MFC after: 3 weeks

Switch over to using the generic joy driver

Cleaned up all headers that include <sys/ioctl.h> or <sys/ioccom.h>:
- don't include <sys/ioctl.h> in any header. Include <sys/ioccom.h>
instead. This was already done in 4.4Lite for the most important
ioctl headers. Header spam currently increases kernel build
times by 10-20%. There are more than 30000 #includes (not counting
duplicates) for compiling LINT.
- include <sys/types.h> if and only it is necessary to make the header
almost self-sufficient (some ioctl headers still need structs from
elsewhere).
- uniformized idempotency ifdefs. Copied the style in the 4.4Lite
ioctl headers.

Put the joystick status in a struct {int x, y, b1, b2;} rather than in a
dummy array of 4 integers. Declare the struct in the header file and update
the man page.

ioctls for the joystick driver