[feature] Upload shipping documents for DHL Express (Paperless Trade / PLT)

[MarcoWel]

It would be crucial for us to be able to upload docs for a DHL Express shipment created via Karrio.

Implementation should be easy, please see here:

• https://www.dhl.de/en/geschaeftskunden/express/infos-knowhow/hilfe-zollabwicklung/plt.html
• https://developer.dhl.com/api-reference/dhl-express-mydhl-api#reference-docs-section/operations-shipment-exp-api-shipments-img-upload

For Fedex, Karrio already supports document upload: #191 For UPS, this feature would be great to have but not as urgent.

[MarcoWel]

Any progress on this one? :)

[danh91]

It was on the backlog. I will bump it up 😄

[danh91]

This is partially supported.

Only works when the documents are sent along with the shipment in a single call.

We will close when direct document upload will be supported.