Add student

...ui/cs/advprog/tutorial0/controller/StudentController.java

...og/tutorial0/exception/DuplicateStudentNameException.java

...ain/java/id/ac/ui/cs/advprog/tutorial0/model/Student.java

...advprog/tutorial0/model/repository/StudentRepository.java

...ui/cs/advprog/tutorial0/model/service/StudentService.java

...s/advprog/tutorial0/model/service/StudentServiceImpl.java

src/main/resources/templates/createStudent.html

src/main/resources/templates/studentList.html