[TASK] Always use Icon API for Module Icons

The Icon API with icon identifiers is now used throughout the 
core when rendering module icons. This avoids some additional
custom code on several places to identify backpaths etc.

Resolves: #73186
Releases: master
Change-Id: Ic146017a25e5872d0f835e7aae5ff6f00755926c
Reviewed-on: https://review.typo3.org/46174


Reviewed-by: Morton Jonuschat <m.jonuschat@mojocode.de>
Tested-by: Morton Jonuschat <m.jonuschat@mojocode.de>
Reviewed-by: Georg Ringer <georg.ringer@gmail.com>
Tested-by: Georg Ringer <georg.ringer@gmail.com>