[HUDI-476]: Add hudi-examples module (#1151)

add hoodie delta streamer mock source example and dfs source and kafka source examples

Signed-off-by: dengziming <dengziming1993@gmail.com>

add defaultSparkConf utils method

change version of hudi-examples to 0.5.2-SNAPSHOT
change the artifcatId of hudi-spark and hudi-utilities
alter some code to adapt kafka2.0

Update scritps

Add license

hudi-examples/bin/hudi-delta-streamer

@@ -0,0 +1,39 @@
+#!/usr/bin/env bash
+
+#  Licensed to the Apache Software Foundation (ASF) under one
+#  or more contributor license agreements.  See the NOTICE file
+#  distributed with this work for additional information
+#  regarding copyright ownership.  The ASF licenses this file
+#  to you under the Apache License, Version 2.0 (the
+#  "License"); you may not use this file except in compliance
+#  with the License.  You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+#  Unless required by applicable law or agreed to in writing, software
+#  distributed under the License is distributed on an "AS IS" BASIS,
+#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#  See the License for the specific language governing permissions and
+# limitations under the License.
+
+EXAMPLES_DIR="$(dirname $(dirname "${BASH_SOURCE[0]}"))"
+PROJECT_DIR="$(dirname ${EXAMPLES_DIR})"
+
+JAR_FILE=`ls ${PROJECT_DIR}/packaging/hudi-utilities-bundle/target/hudi-utilities-bundle_*.jar | grep -v sources | grep -v tests.jar`
+EXAMPLES_JARS=`ls ${PROJECT_DIR}/hudi-examples/target/hudi-examples-*.jar | grep -v sources | grep -v tests.jar`
+
+if [ -z "${SPARK_MASTER}" ]; then
+  SPARK_MASTER="yarn-cluster"
+fi
+
+exec "${SPARK_HOME}"/bin/spark-submit \
+--master ${SPARK_MASTER} \
+--conf spark.serializer="org.apache.spark.serializer.KryoSerializer" \
+--conf spark.kryoserializer.buffer.max=128m \
+--conf spark.yarn.queue=root.default \
+--conf spark.yarn.submit.waitAppCompletion=false \
+--packages org.apache.spark:spark-avro_2.11:2.4.4 \
+--jars ${EXAMPLES_JARS} \
+--class org.apache.hudi.utilities.deltastreamer.HoodieDeltaStreamer \
+"${JAR_FILE}" \
+$@