[FEATURE] The tutor can add a course and it's contents.

**Is your feature request related to a problem? Please describe.**
The courses will have to be created by the tutor.

**Describe the solution you'd like**
A tutor will add a course by providing its name and a little detailed explanation about the course, then add it's content. He'll have to publish it to be accessible to students.

**Describe alternatives you've considered**
Create the course and it's contents at once instead of creating the course first then adding its contents later.

The issue names no files, tests, or entry points. First clarify the course and content structure, tutor-facing workflow, publishing behavior, and student access criteria; done should include agreed requirements and tests for creating, adding content to, publishing, and viewing a course.

Written by the indexing model from the issue text.