[FEATURE] Hook to modify the display results before FluidView assignment

To modify the display result rows before data is assigned to the fluid
view there is a new hook inside the `getDisplayResults()` method
called `getDisplayResults_postProc`.

Resolves: #82488
Releases: master
Change-Id: I2f0ac073692fb28b9c71a18def027c71a418606f
Reviewed-on: https://review.typo3.org/54148


Reviewed-by: Jigal van Hemert <jigal.van.hemert@typo3.org>
Tested-by: Jigal van Hemert <jigal.van.hemert@typo3.org>