Merge branch 'merge-362-into-5.0' of https://gitlab.studip.de/marcus/studip into 5.0

app/controllers/course/courseware.php

lib/classes/JsonApi/Routes/Courseware/Authority.php

...i/Routes/Courseware/BookmarkedStructuralElementsIndex.php

...ses/JsonApi/Routes/Courseware/CoursewareInstancesShow.php

...outes/Courseware/DescendantsOfStructuralElementsIndex.php

...ses/JsonApi/Routes/Courseware/StructuralElementsIndex.php

...sses/JsonApi/Routes/Courseware/StructuralElementsShow.php

lib/classes/JsonApi/Schemas/Courseware/StructuralElement.php

lib/models/Courseware/StructuralElement.php

...es/vue/components/courseware/CoursewareManagerElement.vue

resources/vue/components/courseware/CoursewareRibbon.vue

...vue/components/courseware/CoursewareStructuralElement.vue

.../components/courseware/CoursewareTableOfContentsBlock.vue

...ces/vue/components/courseware/CoursewareToolsContents.vue

resources/vue/components/courseware/CoursewareTree.vue

resources/vue/components/courseware/CoursewareTreeItem.vue

resources/vue/components/courseware/IndexApp.vue

resources/vue/components/courseware/ManagerApp.vue

resources/vue/courseware-index-app.js

resources/vue/courseware-manager-app.js