add support for query filtering

[etrandafir93]

hey, thanks for the time and effort invested in this component.

we would need the ability to send some filtering fields to the dataProvider through the InnerQuery.

the api would look like this:

@Data
public static class CustomFilter {
    private String name;
}

[...]

PaginatedGrid<Person, CustomFilter> grid = new PaginatedGrid<>();
grid.setDataProvider(personService);
grid.setFilter(filter);

and, on the dataProvider:

PersonService extends AbstractBackEndDataProvider<Person, CustomFilter> {

[...]

    @Override
    protected Stream<BonusWalletDefinition> fetchFromBackEnd(Query<BonusWalletDefinition, CustomFilter> query) {
    CustomFilter filter = query.getFilter().orElseThrow();
        return findByName( filter.getName() );
    }

}

do you have something similar or do you think something like this can be added? I would really need this.

Thank you, Emanuel