CDF-20144: remove wdl tests and mark deprecated (#856)

wdl didn't hit GA and has no active usage through Scala SDK
and so no active usage through spark-datasource either.

Let's start by removing tests and marking deprecated.
Removing tests has a benefit of getting closer to being able
to run repo tests in any project (wdl tests can only be run in
dedicated projects with wdl access anyway).

[CDF-20144]

build.sbt

@@ -28,7 +28,7 @@ lazy val commonSettings = Seq(
   organization := "com.cognite.spark.datasource",
   organizationName := "Cognite",
   organizationHomepage := Some(url("https://cognite.com")),
-  version := "3.4." + patchVersion,
+  version := "3.5." + patchVersion,
   isSnapshot := patchVersion.endsWith("-SNAPSHOT"),
   crossScalaVersions := supportedScalaVersions,
   semanticdbEnabled := true,

src/main/scala/cognite/spark/v1/wdl/JsonObjectToRow.scala

@@ -5,6 +5,7 @@ import io.circe.{Json, JsonObject}
 import org.apache.spark.sql.Row
 import org.apache.spark.sql.types._
 
+@deprecated("wdl support is deprecated", since = "0")
 object JsonObjectToRow {
   implicit class RequiredOption[T](optionValue: Option[T]) {
     def orThrow(structFieldName: String, nullable: Boolean, dataType: DataType): Option[T] =

src/main/scala/cognite/spark/v1/wdl/RowToJson.scala

@@ -14,6 +14,7 @@ import java.time.{Instant, LocalDate}
 import scala.collection.mutable
 
 // sscalastyle:off
+@deprecated("wdl support is deprecated", since = "0")
 object RowToJson {
 
   /**

src/main/scala/cognite/spark/v1/wdl/WdlExceptions.scala

@@ -3,10 +3,12 @@ package cognite.spark.v1.wdl
 import cognite.spark.v1.CdfSparkException
 import org.apache.spark.sql.types.DataType
 
+@deprecated("wdl support is deprecated", since = "0")
 class RequiredFieldIsNullException(val structFieldName: String, val dataType: DataType)
     extends CdfSparkException(
       s"Required field `${structFieldName}` of type `${dataType.typeName}` should not be NULL.")
 
+@deprecated("wdl support is deprecated", since = "0")
 class WrongFieldTypeException(
     val structFieldName: String,
     val expectedDataType: DataType,