Consider new or overhauled DateFormField #6542
Description
The existing DateFormField has multiple design flaws that are probably difficult to solve in a backward compatible way.
ref https://www.woltlab.com/community/thread/295616-dateformfield-speichert-minuten-und-sekunden-bei-supportstime-false/
ref https://www.woltlab.com/community/thread/301400-dateformfield-savevalueformat-savevalueformat-wann-verwenden/
ref https://www.woltlab.com/community/thread/306131-utc-zeitzone-timestamp-des-dateformfields/