[TASK] Doctrine: migrate part 1 of class DataHandler

Resolves: #77332
Releases: master
Change-Id: Ib9b34636dbb0f097f56818ed363c863d88c70896
Reviewed-on: https://review.typo3.org/49288


Reviewed-by: Morton Jonuschat <m.jonuschat@mojocode.de>
Tested-by: Bamboo TYPO3com <info@typo3.com>
Reviewed-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Tested-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Reviewed-by: Oliver Hader <oliver.hader@typo3.org>
Tested-by: Oliver Hader <oliver.hader@typo3.org>