Refactor web for better cq

[A-lexisL]

• change CourseList, CourseDetail, Review to classy views
• add sort and filter to CourseList
• combine courses/id/reviews/my to courses/id/reviews/ with request_param
• define UserReviewAPI and registered under reviews/id/
• transform ReviewForm to ReviewSerializer
• limits the PUT permission for UserReviewAPI
• professors_api & instructors_api
• use modern path? / add urls.py for each app
• enhance sort and filter for reviews
• fix pitfalls in Code Review #33
• add types hint