Display "Werk" in Annotation panel with link to the bibliography

For displaying an annotation, in this case a "werk", Tido needs a corresponding id on text panel side which is in this case not provided since the "werk" should point to the corresponding bibliography entry. At the moment this is already implemented, however, due to above issue the "werke" can not be displayed. To resolve this Tido should be adapted so that it can display annotation without corresponding id on text panel side.