Crates GroupDAO & CourseDAO, also added method in ApplicantDAO getAllApplicantsId
Changed annotations in entities and added 2 methods in GroupDAO(removeGroup & updateGroup)
Group has unique name/ Some changes in Entities.
Merge branch 'develop' into feature/GroupDao
Merge remote-tracking branch 'origin/develop' into develop

Conflicts:
	user-manager/src/main/java/com/softserveinc/ita/controller/UserController.java