Deprecation: #61829 - Deprecate config.classFile DBAL option 

See forge#61829

Description 

The DBAL option config.classFile has been marked for deprecation, and will be removed with TYPO3 CMS 8.

Impact 

Using config.classFile option will throw a deprecation message.

Affected Installations 

Installations which use a user-defined DBAL database-handler.

Migration 

Load the class using the autoloader.