feat: implementedTaskDAO

...c/main/java/unipotsdam/gf/modules/project/ProjectDAO.java

...n/java/unipotsdam/gf/modules/tasks/ParticipantsCount.java

...schen/src/main/java/unipotsdam/gf/modules/tasks/Task.java

...en/src/main/java/unipotsdam/gf/modules/tasks/TaskDAO.java

...n/src/main/java/unipotsdam/gf/modules/tasks/TaskName.java

...nsamforschen/src/main/webapp/project/js/create-project.js

gemeinsamforschen/src/main/webapp/project/tasks-student.jsp

gemeinsamforschen/src/scripts/dbschema/fltrail.sql

gemeinsamforschen/src/scripts/fltrail_tasks.sql