Adds styleguide as require-dev composer dependency and
call the data generator for acceptance tests.

Change-Id: I917b732face3c9d194ef88bada18e3195562a6dc
Resolves: #75481
Releases: master
Reviewed-on: https://review.typo3.org/47541


Reviewed-by: Sascha Egerer <sascha@sascha-egerer.de>
Tested-by: Sascha Egerer <sascha@sascha-egerer.de>
Reviewed-by: Susanne Moog <typo3@susannemoog.de>
Tested-by: Susanne Moog <typo3@susannemoog.de>