Replace custom converters with DefaultFormattingConversionService

[scordio]

This change replaces almost all existing custom converters with the Spring Framework's DefaultFormattingConversionService built-in features. The Date converters have been replaced with a custom formatter because the existing Spring Batch logic is incompatible with what the framework can offer.

DefaultFormattingConversionService also supports ZonedDateTime and OffsetDateTime out of the box; therefore, this PR also resolves #5178 and is an alternative to #5179.

[scordio]

Since all existing converters are public, I proposed deprecating them for removal in 6.3. Let me know if I should make any adjustments to it.

[fmbenhassine]

That's how I would do it as well 👍

[fmbenhassine]

Thank you for the PR! It's always better to leverage what we can from Spring Framework indeed. I will plan this for 6.1.

I am just not sure yet if we really need the ConversionServiceFactory with a static factory method, but I will come back to that in detail when I start working on 6.1.

[scordio]

I am just not sure yet if we really need the ConversionServiceFactory with a static factory method

I created that because the ConversionService is instantiated five times in the codebase in exactly the same way, so I thought it would be better to centralize it instead of repeating the following:

FormattingConversionService conversionService = new DefaultFormattingConversionService();
conversionService.addFormatterForFieldType(Date.class, new DateFormatter());

DateTimeFormatterRegistrar dateTimeFormatterRegistrar = new DateTimeFormatterRegistrar();
dateTimeFormatterRegistrar.setUseIsoFormat(true);
dateTimeFormatterRegistrar.registerFormatters(conversionService);

But I'm totally fine to inline it in those places or go in a different direction I haven't thought of, just let me know your preference 🙂