Breaking: #45899 - Split class ImportExport into classes Import and Export 

See forge#45899

Description 

Class TYPO3CMSImpexpImportExport (typo3/sysext/impexp/Classes/ImportExport.php) has been split into a class dedicated for import and another one for export.

Impact 

Using and extending the class is not possible anymore.

Affected Installations 

Extensions using the class and its methods directly or extending the class.

Migration 

Use or extend one or both of the new classes (TYPO3CMSImpexpImport and TYPO3CMSImpexpExport).