[TASK] IconViewHelper should generate absolute URLs

This change allows the IconViewHelper in the reports module
to be used not just from typo3/ (e.g. if a person puts typo3/index.php
to a different place or wants to show the reports in the install tool).

Resolves: #76322
Releases: master
Change-Id: I7067654b3fff5ac75fb9883b708ddb28a9ddc7d1
Reviewed-on: https://review.typo3.org/48321


Reviewed-by: Morton Jonuschat <m.jonuschat@mojocode.de>
Tested-by: Morton Jonuschat <m.jonuschat@mojocode.de>
Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Tested-by: Wouter Wolters <typo3@wouterwolters.nl>
Reviewed-by: Frank Naegler <frank.naegler@typo3.org>
Tested-by: Frank Naegler <frank.naegler@typo3.org>