Update AUTHORS list, add commentary

Reviewed-by: Paul Dale <paul.dale@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/6602)

AUTHORS

@@ -1,15 +1,29 @@
+# This is the list of OpenSSL authors for copyright purposes.
+#
+# This does not necessarily list everyone who has contributed code, since in
+# some cases, their employer may be the copyright holder.  To see the full list
+# of contributors, see the revision history in source control.
+OpenSSL Software Services, Inc.
+OpenSSL Software Foundation, Inc.
+
+# Individuals
 Andy Polyakov
 Ben Laurie
-    Bodo Möller
-    Emilia Käsper
+Ben Kaduk
+Bernd Edlinger
+Bodo Möller
+David Benjamin
+Emilia Käsper
 Eric Young
 Geoff Thorpe
 Holger Reif
 Kurt Roeckx
-    Lutz Jänicke
+Lutz Jänicke
 Mark J. Cox
 Matt Caswell
+Matthias St. Pierre
 Nils Larsch
+Paul Dale
 Paul C. Sutton
 Ralf S. Engelschall
 Rich Salz
@@ -17,5 +31,5 @@
 Stephen Henson
 Steve Marquess
 Tim Hudson
-    Ulf Möller
+Ulf Möller
 Viktor Dukhovni