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.
I think we can remove this line. It makes sense in this context, but for other apps that have ``POST`` requests etc, using a browser doesn't always make sense. So, to maintain consistency...