Add check for users and add manage page

Frontend/quizz-game/src/app/app-routing.module.ts

Frontend/quizz-game/src/app/app.module.ts

...zz-game/src/app/login/errorlogin/errorlogin.component.css

...z-game/src/app/login/errorlogin/errorlogin.component.html

...ame/src/app/login/errorlogin/errorlogin.component.spec.ts

...izz-game/src/app/login/errorlogin/errorlogin.component.ts

Frontend/quizz-game/src/app/login/login.service.spec.ts

Frontend/quizz-game/src/app/login/login.service.ts

...d/quizz-game/src/app/login/sign-in/sign-in.component.html

...end/quizz-game/src/app/login/sign-in/sign-in.component.ts

...d/quizz-game/src/app/login/sign-up/sign-up.component.html

...end/quizz-game/src/app/login/sign-up/sign-up.component.ts

Frontend/quizz-game/src/app/manage/manage.component.css

Frontend/quizz-game/src/app/manage/manage.component.html

Frontend/quizz-game/src/app/manage/manage.component.spec.ts

Frontend/quizz-game/src/app/manage/manage.component.ts