[FEATURE] Endpoint for add/edit (for both) teacher schedule

[hamidsultanzadeh]

Endpoint: POST /v1/teachers/schedule (new controller)

A teacher should be able to update/insert a weekly schedule for himself/herself

Technical notes:

1. Investigate merge in SQL. it will help you to update/insert (depending on the existence of data) in one method. Let me know when you are stuck on this.
2. It would be great to use a structure for payload

TeacherSchedulePayload {
    Map<DayOfWeek, TeacherScheduleData> entries; 

    static class TeacherScheduleData {
    }
}