Add Gentoo/Lunar/Redhat Init Scripts

Every distribution has slightly different requirements for their
init scripts. Because of this the zfs package contains several
init scripts for various distributions. These scripts have been
contributed by, and are supported by, the larger zfs community.
Init scripts for Gentoo/Lunar/Redhat have been contributed by:

Gentoo - devsk <devsku@gmail.com>
Lunar  - Jean-Michel Bruenn <jean.bruenn@ip-minds.de>
Redhat - Fajar A. Nugraha <list@fajar.net>