task implementation student

...java/id/ac/ui/tutorial0/controller/StudentController.java

...ui/tutorial0/exception/DuplicateStudentNameException.java

src/main/java/id/ac/ui/tutorial0/model/Student.java

...java/id/ac/ui/tutorial0/repository/StudentRepository.java

src/main/java/id/ac/ui/tutorial0/service/StudentService.java

...n/java/id/ac/ui/tutorial0/service/StudentServiceImpl.java

src/main/resources/templates/createStudent.html

src/main/resources/templates/studentList.html