Add GROUP BY to graphql cql-first

[polandll]

@DisplayName("Should execute query with groupBy") public void groupBy(@TestKeyspace CqlIdentifier keyspaceId) { Map<String, Object> response = CLIENT.executeDmlQuery( keyspaceId, "{ readings(value: {id: 1}, groupBy: {month: true, year: true}) { " + "values { " + " id" + " year " + " month " + " totalValue: _decimal_function(name: "sum", args: ["value"]) } }" + "}");