[fpc-pascal] DB test framework GUI: added database selector

[Reinier Olislagers]

Hi all,

Could you have a look at
23483: [Patch] Add database.ini selection/edit form to dbtestframework_gui

... I've added a database.ini connector selector/editor form that may be
handy to quickly select a database to be edited.

However, I'm not sure this is the best way of using it - it currently is
shown modally before the main test runner form.

Thanks,
Reinier