tree-wide: drop copyright headers from frequent contributors

Fixes #9320.

for p in Shapovalov Chevalier Rozhkov Sievers Mack Herrmann Schmidt Rudenberg Sahani Landden Andersen Watanabe; do
  git grep -e 'Copyright.*'$p -l|xargs perl -i -0pe 's|/([*][*])?[*]\s+([*#]\s+)?Copyright[^\n]*'$p'[^\n]*\s*[*]([*][*])?/\n*|\n|gms; s|\s+([*#]\s+)?Copyright[^\n]*'$p'[^\n]*\n*|\n|gms'
done

man/systemd.netdev.xml

@@ -4,8 +4,6 @@
 
 <!--
   SPDX-License-Identifier: LGPL-2.1+
-
-  Copyright © 2013 Tom Gundersen
 -->
 
 <refentry id="systemd.netdev" conditional='ENABLE_NETWORKD'>