Support single json object in validation about jcv-db

[leomillon]

@philippeagra what's the problem with [] wrapping?

dBComparatorBuilder
        .build("select * from person")
        .isValidAgainst("""
          [{
            "id": "{#uuid#}",
            "name": "test",
          }]
        """

[philippeagra]

@leomillon There is no problem with it but a bit like spring-data differentiates the findOne and findAll for the same select request, unwrapping the expected row into a single json object makes sence for me.
I think that most of the time you will make assertions on a single row (adding a where clause) and the unwrapped array will improve readability.