feat: Create DRF for course grading (#32399)

[kaustavb12]

Description

(cherry picked from commit dea67f2)

This PR creates APIs to GET and POST course grade settings. This is a port of the upstream PR openedx#32399

Supporting information

Link to other information about the change, such as Jira issues, GitHub issues, or Discourse discussions.
Be sure to check they are publicly readable, or if not, repeat the information here.

Testing instructions

1. Setup branch in devstack
2. Fetch Access Token:

   curl -X POST -d "grant_type=client_credentials&client_id=studio-backend-service-key&client_secret=studio-backend-service-secret&token_type=jwt" http://localhost:18000/oauth2/access_token
   

   You will get a response of the format:

   {"access_token": "ACCESS_TOKEN", "expires_in": 36000, "token_type": "JWT", "scope": "read write email profile"}
   

3. Fetch Course Grade Settings (Replace <ACCESS_TOKEN>)

   curl -X GET -H "Authorization: JWT <ACCESS_TOKEN>" http://localhost:18010/api/contentstore/v1/course_grading/course-v1:edX+DemoX+Demo_Course
   

   You will get response of the format:

   {"graders":[{"type":"Homework","min_count":3,"drop_count":1,"short_label":"Ex","weight":75,"id":0},{"type":"Exam","min_count":1,"drop_count":0,"short_label":"","weight":25,"id":1}],"grade_cutoffs":{"A":0.8, "B": 0.6},"grace_period":{"hours":5,"minutes":0},"minimum_grade_credit":0.8,"is_credit_course":false}
   

4. Change Course Grade Settings (Replace <ACCESS_TOKEN>)

   curl -X POST -d '{"graders":[{"type":"Homework","min_count":3,"drop_count":1,"short_label":"Ex","weight":75,"id":0},{"type":"Exam","min_count":1,"drop_count":0,"short_label":"","weight":25,"id":1}],"grade_cutoffs":{"A+":0.9,"A":0.8, "B+":0.7, "B": 0.6, "C": 0.55, "D": 0.5},"grace_period":{"hours":5,"minutes":0},"minimum_grade_credit":0.8}' -H "Authorization: JWT <ACCESS_TOKEN>" -H "Content-Type: application/json" http://localhost:18010/api/contentstore/v1/course_grading/course-v1:edX+DemoX+Demo_Course
   

   You will get response of the format:

   {"graders":[{"type":"Homework","min_count":3,"drop_count":1,"short_label":"Ex","weight":75,"id":0},{"type":"Exam","min_count":1,"drop_count":0,"short_label":"","weight":25,"id":1}],"grade_cutoffs":{"A+":0.9,"A":0.8,"B+":0.7,"B":0.6,"C":0.55,"D":0.5},"grace_period":{"hours":5,"minutes":0},"minimum_grade_credit":0.8}
   

Deadline

"None" if there's no rush, or provide a specific date or event (and reason) if there is one.

Other information

BB-7660

[Cup0fCoffee]

👍 Good to merge once the quality checks are fixed.

• [-] I tested this: same changes have been tested already
• I read through the code
• Includes documentation
• I made sure any change in configuration variables is reflected in the corresponding client's configuration-secure repository.