Add tests to filter types and fix options

[franmomu]

Subject

I wanted to work a bit with filters, but before starting, better to have some tests.

Adding them showed that:

• format is not valid for DateTimeRangeType because this Type adds two DateTimeType that have that configuration (not DateTimeRangeType itself), so I've added the format option in the field_options option so is passed to those DateTimeType and changed from DateType::HTML5_FORMAT to DateTimeType::HTML5_FORMAT.
• date_format is not valid for DateType, so I've changed it to format.

Another interesting part I was thinking was... why has it worked so far? Because having:

public function configureOptions(OptionsResolver $resolver)
{
    $resolver->setDefaults([
        'field_type' => FormDateType::class,
        'field_options' => ['date_format' => FormDateType::HTML5_FORMAT],
    ]);
}

The field_options option is an array and we always override this array (here for example), and by doing this, it does not merge the values, so this date_format always gets lost.

If we want to allow nested options we should use a closure instead (useful also for #6078), but that's another issue (that I think we should consider).

I am targeting this branch, because these changes are BC.

Changelog

### Fixed
- Fixed using invalid values in `field_options` of filters.

[phansys]

I'll try to check these changes in a real project, but at first sight, they seem right.