Remove $FreeBSD$: one-line sh pattern

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

Move all devfs related files to sbin/devfs/

This is related to pkgbase as it uses CONFS to properly tag these as config
files.

Approved by: will (mentor)
Differential Revision: https://reviews.freebsd.org/D16785