feat: added missing DAOs

...a/unipotsdam/gf/modules/journal/model/JournalDAOImpl.java

...c/main/java/unipotsdam/gf/modules/journal/model/Link.java

...ain/java/unipotsdam/gf/modules/journal/model/LinkDAO.java

...java/unipotsdam/gf/modules/journal/model/LinkDAOImpl.java

...ipotsdam/gf/modules/journal/model/ProjectDescription.java

...tsdam/gf/modules/journal/model/ProjectDescriptionDAO.java

...m/gf/modules/journal/model/ProjectDescriptionDAOImpl.java

...m/gf/modules/journal/service/DummyProjectDescription.java

...java/unipotsdam/gf/modules/journal/util/JournalUtils.java

gemeinsamforschen/src/scripts/dbschema/journal.sql