Add recovered files

...hul/cs2800/model/exception/NoGradeAvailableException.java

.../rhul/cs2800/model/exception/NoRegistrationException.java

...k/ac/rhul/cs2800/model/NoGradeAvailableExceptionTest.java

.../uk/ac/rhul/cs2800/model/NoRegistrationExceptionTest.java

...nagement/src/main/java/uk/ac/rhul/cs2800/model/Grade.java

...agement/src/main/java/uk/ac/rhul/cs2800/model/Module.java

...t/src/main/java/uk/ac/rhul/cs2800/model/Registration.java

...gement/src/main/java/uk/ac/rhul/cs2800/model/Student.java

...ment/src/test/java/uk/ac/rhul/cs2800/model/GradeTest.java

...ent/src/test/java/uk/ac/rhul/cs2800/model/ModuleTest.java

...c/test/java/uk/ac/rhul/cs2800/model/RegistrationTest.java

...nt/src/test/java/uk/ac/rhul/cs2800/model/StudentTest.java