[BUGFIX] MM references are not transformed to versioned entities

Scenario:
* within a workspace
* using a MM intermediate table for relations
* having versioned entities on both sides of the relation to be defined
* however, the live uids of the entities are submitted to the data handler

Problem:
* MM relation is created with the live uids on one side

Solution:
* convert submitted relation uids to accordant version uids in workspace

Resolves: #77375
Releases: master, 7.6
Change-Id: Id099845258d3e2820ac9c369acc0339689b768a9
Reviewed-on: https://review.typo3.org/49338


Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Markus Klein <markus.klein@typo3.org>
Reviewed-by: Stefan Neufeind <typo3.neufeind@speedpartner.de>
Tested-by: Benni Mack <benni@typo3.org>
Reviewed-by: Susanne Moog <susanne.moog@typo3.org>
Tested-by: Susanne Moog <susanne.moog@typo3.org>