[FEATURE] Show Nextcloud Deck Cards from the configured Stack

[pbek]

It would be great to show the Nextcloud Deck Cards from the configured Stack in a dialog.

https://deck.readthedocs.io/en/latest/API

[pbek]

25.9.0

• The Nextcloud Deck dialog can now show the cards from the stack (no editing yet)
  (for #3357)