[TASK] Enforce optimized composer autoloader

The optimized autoload generation gives a huge benefit in performance.
Let people participate from this benefit even if they do not know about it.

Add this option in composer.json, so that this step cannot be forgotten when
creating distribution builds.

Resolves: #70436
Releases: master, 6.2
Change-Id: Ia3e1a3209f3c6820f514d2574a3c71cacd4e8501
Reviewed-on: http://review.typo3.org/43861


Reviewed-by: Markus Klein <markus.klein@typo3.org>
Tested-by: Markus Klein <markus.klein@typo3.org>
Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Tested-by: Wouter Wolters <typo3@wouterwolters.nl>