Fix performance of building row-level results (#577)

* Generate row-level results with withColumns

Iteratively using withColumn (singular) causes performance
issues when iterating over a large sequence of columns.

* Add back UNIQUENESS_ID

src/main/scala/com/amazon/deequ/VerificationResult.scala

@@ -98,9 +98,7 @@ object VerificationResult {
     val columnNamesToMetrics: Map[String, Column] = verificationResultToColumn(verificationResult)
 
     val dataWithID = data.withColumn(UNIQUENESS_ID, monotonically_increasing_id())
-    columnNamesToMetrics.foldLeft(dataWithID)(
-      (dataWithID, newColumn: (String, Column)) =>
-        dataWithID.withColumn(newColumn._1, newColumn._2)).drop(UNIQUENESS_ID)
+    dataWithID.withColumns(columnNamesToMetrics).drop(UNIQUENESS_ID)
   }
 
   def checkResultsAsJson(verificationResult: VerificationResult,