[TASK] Remove typo3/gfx

As all occurences are removed for now, the clear.gif icon and the whole
gfx/ directory can be removed as well.

Releases: master
Resolves: #25024
Change-Id: I2e87ccffdc1b27d2a78684b50bf47533d59ceb67
Reviewed-on: http://review.typo3.org/42299


Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Tested-by: Wouter Wolters <typo3@wouterwolters.nl>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Tested-by: Anja Leichsenring <aleichsenring@ab-softlab.de>