[FEATURE] Show PHP Errors after checking compatibility of extensions

The errors are logged in another log file and loaded as json afterwards.

Change-Id: I63458c0a4f64e6d8f4236667b6d22ff6b50aa1f3
Resolves: #51362
Releases: 6.2
Reviewed-on: https://review.typo3.org/28298
Reviewed-by: Tomita Militaru
Reviewed-by: Ernesto Baschny
Tested-by: Ernesto Baschny
Reviewed-by: Dmitry Dulepov
Tested-by: Dmitry Dulepov