Breaking: #68131 - Streamline error and exception handling 

See forge#68131

Description 

It is not possible any more to change error and exception handling configuration in an ext_localconf.php of an extension.

Impact 

Error or exception handling configuration overridden in ext_localonf.php files will not work any more.

Affected Installations 

All installations with extension that set error or exception handling configuration in ext_localconf.php files.

Migration 

Configure error and exception handling in LocalConfiguration.php or AdditionalConfiguration.php