Reorganize source files into logical subdirectories

Co-authored-by: Hirek193 <23196899+Hirek193@users.noreply.github.com>

simulation/simulationsounds.cpp

@@ -0,0 +1,22 @@
+/*
+This Source Code Form is subject to the
+terms of the Mozilla Public License, v.
+2.0. If a copy of the MPL was not
+distributed with this file, You can
+obtain one at
+http://mozilla.org/MPL/2.0/.
+*/
+
+#include "stdafx.h"
+#include "simulationsounds.h"
+
+#include "utilities.h"
+
+namespace simulation {
+
+sound_overridemap Sound_overrides;
+sound_table Sounds;
+
+} // simulation
+
+//---------------------------------------------------------------------------