Mahmoud Khalil authored Oct 01, 2021 and Albert Astals Cid committed Oct 01, 2021

By using Poppler 20.10 new custom image stamps APIs

Instead of the incompatible hack we used before that only worked for Okular.

This is done by modifying the update function used by PopplerAnnotationProxy in order to load the image in
the correct dimensions and send it to the poppler-Qt5 frontend.

We temporarily store the stamp annotation appearance when deleting it so that we can set it again when doing an undo undo.