feature/gajendran - Added the Online E-learning platform

[gajendranasokkumar]

Online E - learning Platform

• User Class: Represents students or instructors with attributes like name, email, and password. Users can enroll in courses, make payments, and store quiz results.
• Course Class: Represents courses with attributes like name, type, and description. It maintains lists of students, quizzes, and course content.
• CourseContent Class: Represents different types of content within a course.
• Quiz Class: Represents quizzes associated with a course, with attributes like marks.
• Result Class: Stores quiz scores for students.
• Enrollment Class: Tracks user enrollments with an enrollment date and completion status.
• Payment Class: Represents a payment made by a user for a course.