[BUGFIX] Allow overriding of image manipulation crop ratios

It is not possible to change or override crop ratios via TSconfig
for sys_file_reference (e.g. for a specific user or page tree branch),
thus making the cropping functionality a pain for bigger sites.

Setting a FormEngine option as expected like
  TCEFORM.sys_file_reference.crop.config.ratios.2\.15 = Widescreen
does now work.

Resolves: #77159
Releases: master, 7.6
Change-Id: I9b1366ed4339150c366fc36a814a251cc407afaa
Reviewed-on: https://review.typo3.org/49122


Reviewed-by: Benni Mack <benni@typo3.org>
Tested-by: Benni Mack <benni@typo3.org>