CDAP-540: Ported RecommendMovieProcedure to MovieRecommendService.

Implemented the MovieRecommendService in according to the RecommendMovieProcedure.
Old implementation is still available to compatibility with current user guides.
Which method? We do have the sendJson method (http://docs.cask.co/cdap/current/en/javadocs/co/cask/cdap/api/service/http/HttpServiceResponder.html#sendJson(java.lang.Object))

or you mean one that can take `ObjectStore`?