[BUGFIX] Missing phpinfo() module in install tool

Adds phpinfo() information in System Environment section from
the Install Tool, after warning / error messages.

Fixes: #53271
Releases: 6.2
Change-Id: I8582a65247de998f373d3143f013fa91cb47bff9
Reviewed-on: https://review.typo3.org/25263
Reviewed-by: Oliver Hader
Tested-by: Oliver Hader
Reviewed-by: Stefan Neufeind
Tested-by: Stefan Neufeind
Reviewed-by: Philipp Gampe
Tested-by: Philipp Gampe