For security purposes many applications have moved the configuration files out of the data folder.
PHP and MySQL are two that come to mind.
The postgresql.conf and the pg_hba.conf should NOT be stored in the database data directory. These files
should NOT be owned or editable by the postgres user (OS user that postmaster is running as).
I believe this is a matter of default configuration and that what you described is possible (if maybe not trivial depend on installation method and auto-start setup).
David J.
