Implemented FS#1448 - one database user name and multiple databases

install/sql/incremental/upd_0039.sql

install/sql/ispconfig3.sql

interface/lib/classes/db_mysql.inc.php

interface/web/sites/database_del.php

interface/web/sites/database_edit.php

interface/web/sites/database_user_del.php

interface/web/sites/database_user_edit.php

interface/web/sites/database_user_list.php

interface/web/sites/form/database.tform.php

interface/web/sites/form/database_user.tform.php

interface/web/sites/lib/lang/de_database.lng

interface/web/sites/lib/lang/de_database_list.lng

interface/web/sites/lib/lang/de_database_user.lng

interface/web/sites/lib/lang/de_database_user_admin_list.lng

interface/web/sites/lib/lang/de_database_user_list.lng

interface/web/sites/lib/lang/en_database.lng

interface/web/sites/lib/lang/en_database_user.lng

interface/web/sites/lib/lang/en_database_user_admin_list.lng

interface/web/sites/lib/lang/en_database_user_list.lng

interface/web/sites/lib/module.conf.php