DB: Add drop script compatible with MySQL 8

Author: jackpoz

sql/create/drop_mysql_8.sql

@@ -0,0 +1,9 @@
+REVOKE ALL PRIVILEGES, GRANT OPTION FROM 'trinity'@'localhost';
+
+DROP USER 'trinity'@'localhost';
+
+DROP DATABASE IF EXISTS `world`;
+
+DROP DATABASE IF EXISTS `characters`;
+
+DROP DATABASE IF EXISTS `auth`;