New flashcards from PDF at cursor position (and not at the end of the document)

At the moment newly created flashcards from PDFs are always inserted at the bottom of the document.

New cards should be added at the cursor position and therefore it it possible to control the flow of flashcards in the document.

This helps especially to have a way better consistency with flashcards order and pdf - very useful for larger documents and a lot of flashcards.