WICKET-5436 Implement BigIntegerConverter
WICKET-5437 When a ConversionException is thrown, its message is not used in the ValidationError
WICKET-5437 When a ConversionException is thrown, its message is not used in the ValidationError

Add a test case
WICKET-5437 When a ConversionException is thrown, its message is not used in the ValidationError

Fix the test
WICKET-5436 Implement BigIntegerConverter

Enable BigIntegerConverter by default