WIP deposit: plupload improvements

* Allows autoupload on file selected.

* Fixes a bug when deleting a file right after uploading it.

* Fix in Blueprint url endpoints for upload urls.

* NOTE Removes check for duplicated file. To enable it, add
  filters: { prevent_duplicates: true } to plupload configuration.

Signed-off-by: Javier Martin Montull <javier.martin.montull@cern.ch>
You can keep both routes.

```python
@blueprint.route('/<int:uuid>/file/url/', methods=['POST'])
@blueprint.route('/<depositions:deposition_type>/<int:uuid>/file/url/', methods=['POST'])
```