[TASK] Drop faulty getIcons() method from "Icons" module

The getIcons() implementation of the Icons RequireJS module is faulty and
leads to issues when fetching cached and uncached icons in the same
request. The method is dropped and all calls against that API are
adjusted.

As the API was introduced a week ago, this change is considered being
not breaking.

Resolves: #70881
Releases: master
Change-Id: I62932c48b1482767b3920afe8d320de3ab8623c7
Reviewed-on: https://review.typo3.org/44186


Reviewed-by: Benjamin Kott <info@bk2k.info>
Tested-by: Benjamin Kott <info@bk2k.info>
Reviewed-by: Stefan Neufeind <typo3.neufeind@speedpartner.de>
Tested-by: Stefan Neufeind <typo3.neufeind@speedpartner.de>