[TASK] Reduce App-Icon size in Module menu and Topbar

Decrease size of App-Icons to reduce the visual relevance
from 32x32px to 28x28px. Following paddings and snap mode.

Kudos to Benjamin Kott.

Resolves: #64889
Releases: master
Change-Id: I8e3219cf492415e94dc74d656ef42543bf36cfca
Reviewed-on: http://review.typo3.org/36685


Reviewed-by: Benjamin Kott <info@bk2k.info>
Tested-by: Benjamin Kott <info@bk2k.info>
Reviewed-by: Daniel Maier <dani-maier@gmx.de>
Tested-by: Daniel Maier <dani-maier@gmx.de>
Reviewed-by: Markus Klein <klein.t3@reelworx.at>
Tested-by: Markus Klein <klein.t3@reelworx.at>