Track metrics not involved in any checks

It's possible to store metrics to enable tracking even if they aren't being used in any checks. You will need to provide a metricsPersister to your ChecksSuite as well as your metricsToTrack. For example:

import com.github.timgent.sparkdataquality.checkssuite._
import com.github.timgent.sparkdataquality.metrics.MetricDescriptor.{SizeMetric, SumValuesMetric}
import com.github.timgent.sparkdataquality.metrics.MetricValue.LongMetric
import org.apache.spark.sql.DataFrame

val myDsA: DataFrame = ???
val myDescribedDsA = DescribedDs(myDsA, "myDsA")
val checksSuite = ChecksSuite(
  "someChecksSuite",
  metricsToTrack = Map(
    myDescribedDsA -> Seq(SizeMetric(), SumValuesMetric[LongMetric](onColumn = "number_of_items"))
  )
)