Backend: Generate API function for return result of Student

Generate function to accept id and type of user="student".
So return the marks of the student with the particular id in json format.
if id not found return message "marks details not uploaded Yet."
in case of error return respective message.


The marks of student should be in format-:
```
{
"id":<id of student>,
"sub1":<Subject1 marks>,
.....
......
}
```