[TYPO3-mvc] RFC #11229: Make the Repository unit tests green again and add repository::getObjectType

[Sebastian Kurfürst]

Hey,

for the same reason detailed in #11230 by me, I give my -1 here; as we
would break the upwards-compatibility with FLOW3, and I don't see why a
repository should contain a setter to change the type of objects it is
responsible for. In my opinion, this should rather be done on the
persistence backend side.
Furthermore, the unit tests run green again, and I checked that
everything which you changed in your patch is also verified by the unit
tests; so no need to apply the patch anymore.

Greets,
Sebastian