[FEATURE] Show string value for PHP error codes in install tool

"All configuration" in install tool shows the integer representation
of the bit mask of the PHP error codes in settings like
['SYS']['errorHandlerErrors']. This change adds a view helper to
show the current setting in an E_* constants representation.

Resolves: #51376
Releases: 6.2
Change-Id: Ia69251d97c07b1180f8e7ad99b687b5639396892
Reviewed-on: https://review.typo3.org/23794
Tested-by: Wouter Wolters
Reviewed-by: Christian Kuhn
Tested-by: Christian Kuhn
Reviewed-by: Anja Leichsenring
Tested-by: Anja Leichsenring