This addresses the deprecation described at https://github.blog/changelog/2022-10-11-github-actions-deprecating-save-state-and-set-output-commands/

When the new CSV output mode with the concept of "output drivers" was added in #92, dumping `TRIGGER` definitions was made an implementation detail of the MySQL output driver. This caused `TRIGGER` definitions to be dumped right after the `CREATE TABLE ...` commands, before the actual data `INSERT` statements.

This potentially breaks the generated SQL files, since a newly created trigger may be relevant for the subsequent `INSERT` statements; however, MySQL requires that tables used in the trigger are also included in the `LOCK TABLES` statements.

The aim of this PR is to revert that change, i. e. to dump trigger definitions for a table _after_ the data insert statements for it.

I think it is not necessary to move all trigger definitions to the very end of the output – that is, after _all_ tables have been created and filled with data: A trigger depends on insert/update/deletes for a particular table and is executed only on these events. So, it is not a problem if a trigger refers to a table that has not been created/loaded yet as long as the trigger is not run (and avoiding to run it is the aim of this PR).