XD-990 XD-991 First stage of new hdfs store from shdp

This is a first set of changes to refactor hdfs writing in xd.
- New HdfsStoreMessageHandler which should replace HdfsWritingMessageHandler.
- hdfs.xml sink has been re-written. New options are rolloverSize,
  fileName, directory, codec, idleTimeout, inUseSuffix and inUsePrefix.
- This commit doesn't yet remove anything because existing avro/batch
  code still relies on classes which should go away. These
  will be refactored on a second stage.
- Updated tests HdfsOutboundChannelAdapterIntegrationTests and
  HdfsOutboundChannelAdapterParserTests to check new functionality.
- StoreWriterParser only uses TextFileWriter for now. We need to
  think how we want to support i.e. SequenceFile and Avro formats
  from a user point of view.