feat: URL-stuff replaced by session

...va/unipotsdam/gf/core/management/pageAppearance/Menu.java

...va/unipotsdam/gf/core/management/project/ProjectView.java

.../java/unipotsdam/gf/core/management/user/UserService.java

.../src/main/java/unipotsdam/gf/core/session/GFContexts.java

...orschen/src/main/webapp/annotation/js/annotationScript.js

...n/src/main/webapp/annotation/js/unstructuredAnnotation.js

...schen/src/main/webapp/annotation/js/unstructuredUpload.js

...nsamforschen/src/main/webapp/assessment/js/Quiz-docent.js

gemeinsamforschen/src/main/webapp/assessment/js/Quiz.js

...nsamforschen/src/main/webapp/assessment/js/assess-work.js

...hen/src/main/webapp/assessment/js/assessmentCalculator.js

...nsamforschen/src/main/webapp/assessment/js/create-quiz.js

...orschen/src/main/webapp/assessment/js/rateContribution.js

gemeinsamforschen/src/main/webapp/assessment/js/take-quiz.js

gemeinsamforschen/src/main/webapp/assessment/js/view-quiz.js

gemeinsamforschen/src/main/webapp/core/footer.js

gemeinsamforschen/src/main/webapp/core/overview-docent.js

gemeinsamforschen/src/main/webapp/core/overview-student.js

gemeinsamforschen/src/main/webapp/core/project-student.js

gemeinsamforschen/src/main/webapp/core/showProjects.js