Revise ca_object_representations editor bundle with new user interface supporting:
1. Drag-and-drop upload of one or more media files, with support for setting representation-level metadata for all files in one go.
2. Selectable display modes: grid small, grid large and list
3. Sorting of media on any representation-level metadata field
4. Filtering of displayed media
5. Data display and entry of representation-level metadata directly from the bundle.