[ADD] Add LICENSE and COPYRIGHT

closes #5821

Author: odony

COPYRIGHT

@@ -0,0 +1,13 @@
+Most of the files are
+
+  Copyright (c) 2004-2023 Odoo S.A.
+
+Some files may also contain contributions from third
+parties. In this case the original copyright of
+the contributions can be traced through the
+history of the source version control system.
+
+When that is not the case, the files contain a prominent
+notice stating the original copyright and applicable
+license, or come with their own dedicated COPYRIGHT
+and/or LICENSE file.