[HUDI-2767] Enabling timeline-server-based marker as default (#4112)

- Changes the default config of marker type (HoodieWriteConfig.MARKERS_TYPE or hoodie.write.markers.type) from DIRECT to TIMELINE_SERVER_BASED for Spark Engine.
- Adds engine-specific marker type configs: Spark -> TIMELINE_SERVER_BASED, Flink -> DIRECT, Java -> DIRECT.
- Uses DIRECT markers as well for Spark structured streaming due to timeline server only available for the first mini-batch.
- Fixes the marker creation method for non-partitioned table in TimelineServerBasedWriteMarkers.
- Adds the fallback to direct markers even when TIMELINE_SERVER_BASED is configured, in WriteMarkersFactory: when HDFS is used, or embedded timeline server is disabled, the fallback to direct markers happens.
- Fixes the closing of timeline service.
- Fixes tests that depend on markers, mainly by starting the timeline service for each test.

hudi-spark-datasource/hudi-spark/src/test/scala/org/apache/hudi/functional/TestStructuredStreaming.scala

@@ -59,9 +59,11 @@ class TestStructuredStreaming extends HoodieClientTestBase {
     spark = sqlContext.sparkSession
     initTestDataGenerator()
     initFileSystem()
+    initTimelineService()
   }
 
   @AfterEach override def tearDown() = {
+    cleanupTimelineService()
     cleanupSparkContexts()
     cleanupTestDataGenerator()
     cleanupFileSystem()