sys: Remove $FreeBSD$: one-line sh pattern

Remove /^\s*#[#!]?\s*\$FreeBSD\$.*$\n/

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

MFC r207536, r207696, r208183:
Import mvs(4) - Marvell 88SX50XX/88SX60XX/88SX70XX/SoC SATA controllers
driver for CAM ATA subsystem. This driver supports same hardware as
atamarvell, ataadaptec and atamvsata drivers from ata(4), but provides
many additional features, such as NCQ, PMP, etc.

Import mvs(4) - Marvell 88SX50XX/88SX60XX/88SX70XX/SoC SATA controllers
driver for CAM ATA subsystem. This driver supports same hardware as
atamarvell, ataadaptec and atamvsata drivers from ata(4), but provides
many additional features, such as NCQ, PMP, etc.