[TASK] Utilize grunt-newer to build only changed files

The grunt module `grunt-newer` is introduced to act with changed files
only instead of copying or minifying all files all the time.

Used command:

  yarn add --dev grunt-newer

Resolves: #90200
Releases: master
Change-Id: Idcf34b402f089757a5b5209398abec1bba3288a2
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/63031


Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Susanne Moog <look@susi.dev>
Tested-by: Daniel Goerz <daniel.goerz@posteo.de>
Reviewed-by: Susanne Moog <look@susi.dev>
Reviewed-by: Daniel Goerz <daniel.goerz@posteo.de>