Create missing term attributes datatype foreign key

Missing foreign key should be created for dataTypeId-column in terms_attributes-table, referencing to id-column of terms_attributes_datatype-table, with ON UPDATE CASCADE ON DELETE SET NULL

Before the above foreign key is set up, all values from dataTypeId-column (in terms_attributes-table) that have no corresponding rows in terms_attributes_datatype-table - should be set to NULL

This migration should be executed earlier than 

345-TRANSLATE-2797-tbx-import-damage-datatypes.php

, so migration filename should be something like

344-TRANSLATE-2999-terms_attributes_dataTypeId_fk.sql