NEWS: add contributor list to news file

Unfortunately, github drops the original commiter when a PR is "squashed" (even
if it is only a single commit) and replaces it with some rubbish
github-specific user id. Thus, to make the contributors list somewhat useful,
update the .mailmap file and undo all the weirdness github applied there.

.mailmap

@@ -74,3 +74,18 @@ Thomas H. P. Andersen <phomes@gmail.com>
 Michael Olbrich <m.olbrich@pengutronix.de>
 Douglas Christman <DouglasChristman@gmail.com>
 Alexander Kuleshov <kuleshovmail@gmail.com> <0xAX@users.noreply.github.com>
+Andreas Henriksson <andreas@fatal.se>
+Daniel Rusek <mail@asciiwolf.com>
+Dennis Wassenberg <dennis.wassenberg@secunet.com>
+Reid Price <reid.price@gmail.com>
+Stefan Schweter <stefan@schweter.it>
+Seraphime Kirkovski <kirkseraph@gmail.com>
+Bart Rulon <barron@lexmark.com>
+Richard W.M. Jones <rjones@redhat.com>
+Roman Stingler <coolx67@gmx.at>
+Michael Hoy <rimmington@gmail.com>
+Tiago Levit <liamgliam@gmail.com>
+Eric Cook <llua@users.noreply.github.com>
+Lukáš Nykrýn <lnykryn@redhat.com>
+Heikki Kemppainen <heikki.kemppainen@nokia.com>
+Hendrik Brueckner <hbrueckner@users.noreply.github.com>