You mean you don't want any routines/functions written in Pl/perl or PL/pythin to get executed?If that is what you are looking for them simply drop the extension for these languages or deny privilege to users/public on these extensions.Infact from what I know, these extensions are not there by default, so don't create them at all.
pgsql-general by date:
Соглашаюсь с условиями обработки персональных данных