[Pulsar-Flink] Add Scala Examples

[erenavsarogullari]

Motivation

This PR aims to help Scala community by adding Scala Examples on Flink Connector.

Modifications

1- FlinkPulsarBatchSinkScalaExample is added for PulsarOutputFormat
2- FlinkPulsarBatchCsvSinkScalaExample is added for PulsarCsvOutputFormat
3- FlinkPulsarBatchJsonSinkScalaExample is added for PulsarJsonOutputFormat
4- Extra comments are added to FlinkPulsarBatchSinkExample

[merlimat]

👍

[erenavsarogullari]

rerun java8 tests

[merlimat]

@erenavsarogullari It looks like the license headers do not match exactly the pattern and the checker is rejecting them:

2018-11-27\T\23:38:25.874 [INFO] Checking licenses...
2018-11-27\T\23:38:25.899 [WARNING] Missing header in: /home/jenkins/jenkins-slave/workspace/pulsar_precommit_java8/pulsar-flink/src/test/scala/org/apache/flink/batch/connectors/pulsar/example/FlinkPulsarBatchJsonSinkScalaExample.scala
2018-11-27\T\23:38:25.899 [WARNING] Missing header in: /home/jenkins/jenkins-slave/workspace/pulsar_precommit_java8/pulsar-flink/src/test/scala/org/apache/flink/batch/connectors/pulsar/example/FlinkPulsarBatchCsvSinkScalaExample.scala
2018-11-27\T\23:38:25.899 [WARNING] Missing header in: /home/jenkins/jenkins-slave/workspace/pulsar_precommit_java8/pulsar-flink/src/test/scala/org/apache/flink/batch/connectors/pulsar/example/FlinkPulsarBatchSinkScalaExample.scala
2018-11-27\T\23:38:25.903 [INFO] ------------------------------------------------------------------------

It should get fixed with mvn license:format

[erenavsarogullari]

@merlimat Thanks. Yes, extra whitespace problem has occurred on license. Patch submitted