[TASK] Add check for max_input_vars setting in install tool

This patch add a check for max_input_vars setting.

Resolves: #67978
Related: #64615
Releases: master
Change-Id: Ib8b376184582733c85979a164da6580741472485
Reviewed-on: http://review.typo3.org/40987


Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Reviewed-by: Frederic Gaus <frederic.gaus@flagbit.de>
Tested-by: Frederic Gaus <frederic.gaus@flagbit.de>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>