Initial checkin for Query support for HDS.

HDSQueryOperator  which extends HDSOutputOperator and adds support for querying
ApplicationWithHDSQuery application with kafka integration (not tested).
HDSQueryOperatorTest to unittest HDSQueryOperator class.

Pending
- Query Expiration.
- Handling timeseries (multiple point queries).
Constructors that are only added for Kryo serialization can be private.