Remove $FreeBSD$: one-line sh pattern

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

pkgbase: Create a FreeBSD-nfs package

And move all the nfs related commands there.

Reviewed by: emaste
Differential Revision: https://reviews.freebsd.org/D30754
Sponsored by: Diablotin Systems

Add a command that copies or migrates a data file from one DS to another.

This command can be used by a sysadmin to either copy or migrate a data
file on one DS to another DS.
Its main use is to recover data files onto a mirrored DS after the DS has
been repaired and brought back online.