Sid,Sharvani|#11|Modified dto to not depend on domain.

17|Megha,Ashok|GetAll APIs for course, module, chapter, and messages.
Added status for content dtos

Sid/Sharvani/Megha - All modules generate contentId when created.

Megha|added unit test for get content api for course, module, chapter, message

Ashok | #17 | All course related service APIs can update content, given a contentId with the request.

Ashok | #17 | Refactoring around DTOs

Change-Id: Icd8288f7e7d42ab1c5d4fdbb778d9a09dff16c08