Convert OpenRC to a centralized copyright/license structure

In the past, OpenRC was a hybrid of a centralized and file-scope
license/copyright structure.

I followed the instructions from the Software Freedom Law Center [1] to
convert to a Centralized structure where possible, for easier future
maintenance.

[1] https://softwarefreedom.org/resources/2012/ManagingCopyrightInformation.html

AUTHORS

@@ -0,0 +1,99 @@
+Alessio Ababilov <ilovedevlinux@gmail.com>
+Alexander Berntsen <alexander@plaimi.net>
+Alexander Mezin <mezin.alexander@gmail.com>
+Alexander Tsoy <alexander@tsoy.me>
+Alexander Vershilov <alexander.vershilov@gmail.com>
+Alexander Vershilov <qnikst@gentoo.org>
+Alexander V Vershilov <qnikst@gentoo.org>
+Alexey Shvetsov <alexxy@gentoo.org>
+Alon Bar-Lev <alon.barlev@gmail.com>
+Amadeusz Żołnowski <aidecoe@aidecoe.name>
+Andrew Gregory <andrew.gregory.8@gmail.com>
+Anthony Donnelly <Amzo@archbsd.com>
+Anthony G. Basile <basile@opensource.dyc.edu>
+Anthony G. Basile <blueness@gentoo.org>
+Austin S. Hemmelgarn <ahferroin7@gmail.com>
+Benda Xu <heroxbd@gentoo.org>
+Björn Baumbach <bb@sernet.de>
+Charlie <root@uberlaptop.development.ltl>
+Chris Richards <gizmo@giz-works.com>
+Christian <christian@ch-sc.de>
+Christian Ruppert <idl0r@gentoo.org>
+Christian Wetzig <gentoo@wetzig.de>
+Christopher Head <chead@telus.net>
+Consus <consus@gmx.com>
+Daniel Mierswa <impulze@impulze.org>
+Daniel Robbins <drobbins@funtoo.org>
+Diego Elio Pettenò <flameeyes@flameeyes.eu>
+Diego Elio Pettenò <flameeyes@gmail.com>
+Diego <flameeyes@gentoo.org>
+Dirk Sondermann <ds-gentoo@dyximaq.de>
+Doug Freed <dwfreed@mtu.edu>
+Doug Goldstein <cardoe@cardoe.com>
+Ed Wildgoose <gentoo@wildgooses.com>
+Eray Aslan <eras@gentoo.org>
+Eugeny Shkrigunov <eshkrig@gmail.com>
+Fedja Beader <specing@contact.me.on.irc.freenode.net>
+Flex <frostynova@gmail.com>
+Gabriele Giacone <1o5g4r8o@gmail.com>
+Gary <admin@garyshood.com>
+Gilles Oivier <g.olivier@wanadoo.fr>
+Hank Leininger <hlein@korelogic.com>
+Ian Stakenvicius <axs@gentoo.org>
+Jakob Drexel <jake42@rommel.stw.uni-erlangen.de>
+James Le Cuirot <chewi@aura-online.co.uk>
+Jan Psota <jasiu@belsznica.pl>
+Jason Zaman <jason@perfinion.com>
+Joe Harvell <jharvell@dogpad.net>
+Joe M <joe9mail@gmail.com>
+Johan Bergström <bugs@bergstroem.nu>
+Jory A. Pratt <anarchy@gentoo.org>
+Juan RP <xtraeme@gmail.com>
+Kaarle Ritvanen <kaarle.ritvanen@datakunkku.fi>
+Kfir Lavi <lavi.kfir@gmail.com>
+Kirill Elagin <kirelagin@gmail.com>
+Lars Wendler <polynomial-c@gentoo.org>
+Lorand Kelemen <lorand.kelemen@indgroup.eu>
+Marc Joliet <marcec@gmx.de>
+Marien Zwart <marienz@gentoo.org>
+Michal Gorny <gentoo@mgorny.alt.pl>
+Mihai Moldovan <ionic@ionic.de>
+Mike Frysinger <vapier@gentoo.org>
+Mike Gilbert <floppym@gentoo.org>
+Nao Nakashima <nao.nakashima@gmail.com>
+Natanael Copa <natanael.copa@gmail.com>
+Nathan Phillip Brink <ohnobinki@ohnopublishing.net>
+Ned Ludd <solar@gentoo.org>
+Olivier Huber <oli.huber@gmail.com>
+Patrick Lauer <patrick@gentoo.org>
+Petre Rodan <petre.rodan@simplex.ro>
+Piotr Karbowski <piotr.karbowski@gmail.com>
+Ralph Sennhauser <sera@gentoo.org>
+Richard Yao <ryao@cs.stonybrook.edu>
+Rick Farina (ZeroChaos) <sidhayn@gmail.com>
+Rick Farina (Zero_Chaos) <zerochaos@gentoo.org>
+Robin H. Johnson <robbat2@gentoo.org>
+Robin H. Johnson <robbat2@orbis-terrarum.net>
+Robin Johnson <robbat2@gentoo.org>
+Roy Marples <roy@marples.name>
+Salah Coronya <salah.coronya@gmail.com>
+Sebastian Thorarensen <indigo176@blinkenshell.org>
+Semen Maryasin <marsoft@ya.ru>
+Sergei Trofimovich <slyfox@gentoo.org>
+Seth Robertson <in-gentoo@baka.org>
+S. Gilles <sgilles@umd.edu>
+Stefan Knoblich <s.knoblich@axsentis.de>
+Stef Simoens <stef.simoens@scarlet.be>
+Steve L <slong@rathaus.eclipse.co.uk>
+Steven Chamberlain <steven@pyro.eu.org>
+Svante Signell <svante.signell@gmail.com>
+Sven Vermeulen <sven.vermeulen@siphos.be>
+Thomas D <whissi@whissi.de>
+Thomas Pfaff <tpfaff@gmx.net>
+Trevor Summers Smith <trevorsummerssmith@gmail.com>
+Walter <walter@pratyeka.org>
+William Hubbs <w.d.hubbs@gmail.com>
+William Hubbs <williamh@gentoo.org>
+Will Miles <wmiles@sgl.com>
+Yun Zheng Hu <hu@fox-it.com>
+Yuta SATOH <nigoro.gentoo@0x100.com>