TASK: Make JsonView datetime format configurable
TASK: Make JsonView datetime format configurable

This allows to override the badly chosen default format of DateTimeInterface::ISO8601 which is not really compatible to ISO8601 - see https://www.php.net/manual/en/class.datetimeinterface.php#datetime.constants.iso8601
neos/flow-development-collection,daniellienert/flow-development-collection,kdambekalns/flow-development-collection,kdambekalns/flow-development-collection,dlubitz/flow-development-collection,neos/flow-development-collection,neos/flow-development-collection,dlubitz/flow-development-collection,robertlemke/flow-development-collection,dlubitz/flow-development-collection,fcool/flow-development-collection,daniellienert/flow-development-collection,kdambekalns/flow-development-collection,robertlemke/flow-development-collection,fcool/flow-development-collection,neos/flow-development-collection,fcool/flow-development-collection,robertlemke/flow-development-collection,daniellienert/flow-development-collection,kdambekalns/flow-development-collection,fcool/flow-development-collection,robertlemke/flow-development-collection