Add new file header to use as a base for new files

new-file-header.txt

@@ -0,0 +1,22 @@
+### This header should be used to start new files.
+### It provides an explicit per-file license reference that should be present on all new files.
+### To use this header, delete these lines and the following empty line, modify <filename> to
+### the proper place, and then add new code following the header and a single empty line.
+
+// <filename>
+// Part of the Jellyfin project (https://jellyfin.media)
+//
+//    All copyright belongs to the Jellyfin contributors; a full list can
+//    be found in the file CONTRIBUTORS.md
+//
+//    This program is free software: you can redistribute it and/or modify
+//    it under the terms of the GNU General Public License as published by
+//    the Free Software Foundation, version 2.
+//
+//    This program is distributed in the hope that it will be useful,
+//    but WITHOUT ANY WARRANTY; without even the implied warranty of
+//    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+//    GNU General Public License for more details.
+//
+//    You should have received a copy of the GNU General Public License
+//    along with this program.  If not, see <https://www.gnu.org/licenses/>.