Add a copyright hints file

Signed-off-by: Andrej Shadura <andrew.shadura@collabora.co.uk>

debian/apertis/copyright.yml

+Makefile.in: &automake
+  license: FSFULLR
+  copyright: >
+    1994—2011, Free Software Foundation, Inc.
+src/Makefile.in: *automake
+configure:
+  copyright: 1992-1996, 1998-2012, Free Software Foundation, Inc.
+  license: FSFUL
+aclocal.m4:
+  license: FSFULLR
+debian/*:
+  license: BSD-3-clause
+  copyright: |-
+    1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, Herbert Xu <herbert@debian.org>
+    2004, 2005, 2006, 2007, 2008, 2009, 2010, 2012, 2014, Gerrit Pape <pape@smarden.org>
+    2009, Luk Claes <luk@debian.org>
+    2010, 2011, Jonathan Nieder <jrnieder@gmail.com>
+    2010, Adam D. Barratt <adam@adam-barratt.org.uk>
+    2010, Christian Perrier <bubulle@debian.org>
+    2013, Michael Gilbert <mgilbert@debian.org>
+    2016, Helmut Grohne <helmut@subdivi.de>
+    2016, Mattia Rizzolo <mattia@debian.org>
+    2016, Niels Thykier <niels@thykier.net>
+    2017, Adam Borowski <kilobyte@angband.pl>
+    2017, Ximin Luo <infinity0@debian.org>
+    2018, 2019, Andrej Shadura <andrewsh@debian.org>
+src/bltin/test.c:
+  license: public-domain
+src/bltin/times.c:
+  license: BSD-3-clause