[TASK] Decouple responsibilities in default errorAction()

The default Extbase ActionController::errorAction does a lot
of different things, which makes it hard to customize a controller
to a desired behavior without copying all or some of its code.

Extracting the different responsibilities to separate methods
simplifies such customizations.

Resolves: #55178
Releases: master
Change-Id: I324a504c745649eec11eec65d4e6a718a5e434bd
Reviewed-on: http://review.typo3.org/26944
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Tested-by: Anja Leichsenring <aleichsenring@ab-softlab.de>