Add more bookmark routes to users.

app/controllers/contents/courseware.php

lib/classes/JsonApi/RouteMap.php

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

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

...s/JsonApi/Routes/Courseware/CoursewareInstancesHelper.php

...pi/Routes/Courseware/Rel/BookmarkedStructuralElements.php

...utes/Courseware/Rel/UsersBookmarkedStructuralElements.php

...tes/Courseware/UsersBookmarkedStructuralElementsIndex.php

lib/classes/JsonApi/Schemas/User.php

lib/models/Courseware/Bookmark.php