feat(License): add new headers information about license (#7941)

Co-authored-by: Francesco Borzì <borzifrancesco@gmail.com>

src/cmake/macros/CheckPlatform.cmake

@@ -1,3 +1,15 @@
+#
+# This file is part of the AzerothCore Project. See AUTHORS file for Copyright information
+#
+# This file is free software; as a special exception the author gives
+# unlimited permission to copy and/or distribute it, with or without
+# modifications, as long as this notice is preserved.
+#
+# This program is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY, to the extent permitted by law; without even the
+# implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+#
+
 # check what platform we're on (64-bit or 32-bit), and create a simpler test than CMAKE_SIZEOF_VOID_P
 if(CMAKE_SIZEOF_VOID_P MATCHES 8)
     set(PLATFORM 64)