Remove remainings of mssql

core/command/db/converttype.php

core/js/setup.js

core/templates/installation.php

lib/private/db.php

lib/private/db/connectionfactory.php

lib/private/db/mdb2schemamanager.php

lib/private/db/mssqlmigrator.php

lib/private/setup.php

lib/private/setup/mssql.php

lib/private/setup/mysql.php

tests/lib/db/mdb2schemamanager.php

tests/lib/db/migrator.php

tests/lib/dbschema.php

tests/lib/setup.php