ntp: import ntp-4.2.8p16

Security: NtpBUg3767, NtpBug3808, NtpBug3807 (CVE-2023-26555)
MFC after: immediately

MFV ntp 4.2.8p1 (r258945, r275970, r276091, r276092, r276093, r278284)

Thanks to roberto for providing pointers to wedge this into HEAD.

Approved by: roberto

Flatten the dist and various 4.n.n trees in preparation of future ntp imports.

Virgin import of ntpd 4.0.98f

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

Create the altix project branch. The altix project will add support
for the SGI Altix 350 to FreeBSD/ia64. The hardware used for porting
is a two-module system, consisting of a base compute module and a
CPU expansion module. SGI's NUMAFlex architecture can be an excellent
platform to test CPU affinity and NUMA-aware features in FreeBSD.

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

Virgin import of ntpd 4.0.98f