Deprecation: #73352 - Deprecate old-school AJAX requests 

See forge#73352

Description 

The class TYPO3CMSCoreHttpAjaxRequestHandler and the associated methods ExtensionManagementUtility::registerAjaxHandler() and TYPO3CMSBackendHttpAjaxRequestHandler::dispatchTraditionalAjaxRequest() have been marked as deprecated and will be removed in TYPO3 v9.

Impact 

Calling any of the methods will trigger a deprecation log entry.

Affected Installations 

Any TYPO3 installation with a third-party extensions using the class TYPO3CMSCoreHttpAjaxRequestHandler or calling any of the methods directly.

Migration 

Use the Backend Ajax Routes logic instead.