WL#5608 Assert that all distributed files follow the principle of most restrictive permission possible

- Modified default file permission to 0640.
- Modified default directory permission to 0750
- Modified mysql_install_db to create data directory with permission 0750
- Added mtr test case
- Packaging scripts changes to create data directory with correct
  permission - From RE team

Reviewed-By: Georgi Kodinov <Georgi.Kodinov@Oracle.com>