[HUDI-1089] Refactor hudi-client to support multi-engine (#1827)

- This change breaks `hudi-client` into `hudi-client-common` and `hudi-spark-client` modules 
- Simple usages of Spark using jsc.parallelize() has been redone using EngineContext#map, EngineContext#flatMap etc
- Code changes in the PR, break classes into `BaseXYZ` parent classes with no spark dependencies living in `hudi-client-common`
- Classes on `hudi-spark-client` are named `SparkXYZ` extending the parent classes with all the Spark dependencies
- To simplify/cleanup, HoodieIndex#fetchRecordLocation has been removed and its usages in tests replaced with alternatives

Co-authored-by: Vinoth Chandar <vinoth@apache.org>

hudi-examples/src/main/java/org/apache/hudi/examples/spark/HoodieWriteClientExample.java

@@ -18,8 +18,9 @@
 
 package org.apache.hudi.examples.spark;
 
-import org.apache.hudi.client.HoodieWriteClient;
+import org.apache.hudi.client.SparkRDDWriteClient;
 import org.apache.hudi.client.WriteStatus;
+import org.apache.hudi.client.common.HoodieSparkEngineContext;
 import org.apache.hudi.common.fs.FSUtils;
 import org.apache.hudi.common.model.HoodieAvroPayload;
 import org.apache.hudi.common.model.HoodieKey;
@@ -48,7 +49,7 @@ import java.util.stream.Collectors;
 
 
 /**
- * Simple examples of #{@link HoodieWriteClient}.
+ * Simple examples of #{@link SparkRDDWriteClient}.
  *
  * To run this example, you should
  * <pre>
@@ -94,7 +95,7 @@ public class HoodieWriteClientExample {
               .withDeleteParallelism(2).forTable(tableName)
               .withIndexConfig(HoodieIndexConfig.newBuilder().withIndexType(HoodieIndex.IndexType.BLOOM).build())
               .withCompactionConfig(HoodieCompactionConfig.newBuilder().archiveCommitsWith(20, 30).build()).build();
-      HoodieWriteClient<HoodieAvroPayload> client = new HoodieWriteClient<>(jsc, cfg);
+      SparkRDDWriteClient<HoodieAvroPayload> client = new SparkRDDWriteClient<>(new HoodieSparkEngineContext(jsc), cfg);
 
       // inserts
       String newCommitTime = client.startCommit();