API v2 - Add Support for JSON Arg Input

[Connor-Bernard]

-- Copying from previous GV repo on behalf of @yhwli --

API v2 for Progress Report - JSON URL parameter
### Note: URL Parameter "class" is changed to "course" to maintain naming accuracy and consistency.

Usage:

Path: /

URL Parameters:
    school
    course
    student_mastery
    class_mastery

Path: /json

Content-Type: application/json
Data:
{
  "school": "Berkeley",
  "course": "CS10",
  "student_mastery": {
      "Abstraction": 4,
      "Number Representation": 4,
      "Iteration": 3,
      "Domain and Range": 4,
      "Booleans": 1,
      "Functions": 0,
      "HOFs I": 0
  },
  "class_mastery": {
      "Abstraction": 1,
      "Number Representation": 1,
      "Iteration": 1,
      "Domain and Range": 1,
      "Booleans": 1,
      "Functions": 0,
      "HOFs I": 0
  }

[Connor-Bernard]

[REQUIRED CHANGE]

[Connor-Bernard]

Revise this to remove side effects and just return the student and class mastery