[SPARK-4062][Streaming]Add ReliableKafkaReceiver in Spark Streaming Kafka connector

Add ReliableKafkaReceiver in Kafka connector to prevent data loss if WAL in Spark Streaming is enabled. Details and design doc can be seen in [SPARK-4062](https://issues.apache.org/jira/browse/SPARK-4062).
Please add scala docs describing this class. It should have the information of how it is uses the `store(multipleObjects)` to get more reliability.