_link|download: downloaded external URL to deliver/concatenate - check mimetipe and handle it correctly
- It might be usefull, to download via web, specific attachements like PDF files. (lean > lean-gate)
- A additional parameter, like 'w:', might be used to download an external reference.
- It should be possible to check the downloaded file for a mime type and handle it in a correct way.
- E.g. if the download is a PDF, it could be delivered directly or concatenated.