[TASK] Install Tool: Display a warning if PHP fileinfo extension is not loaded

Show a warning message during the installation process if
the PHP fileinfo extension is not loaded.
It only displays a warning because the fileinfo extension is just
a suggestions and not required.
The fileinfo extension is useful to extract file metadata.

Resolves: #78702
Releases: master, 8.7
Change-Id: Iea0fa087d96d5615056308b7b2fef082b9154a2d
Reviewed-on: https://review.typo3.org/54823


Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Markus Klein <markus.klein@typo3.org>
Tested-by: Markus Klein <markus.klein@typo3.org>