Support HEIC and AVIF images

HEIC uses the HEIF container format, but compressed with the proprietary
HEVC (aka H.265) codec. It is commonly created by iOS devices.

AVIF also uses the HEIF container format, but compresses using the open
AV1 codec.

libheif supports decoding both formats and `heif-gdk-pixbuf` enables
support in the Eye of GNOME viewing application.

Fixes #2110.

debian/control

@@ -62,7 +62,7 @@ Description: This is the SecureDrop workstation template configuration package.
 
 Package: securedrop-workstation-viewer
 Architecture: all
-Depends: securedrop-workstation-config,securedrop-workstation-grsec,apparmor-profiles,apparmor-profiles-extra,apparmor-utils,audacious,eog,evince,file-roller,gedit,totem
+Depends: securedrop-workstation-config,securedrop-workstation-grsec,apparmor-profiles,apparmor-profiles-extra,apparmor-utils,audacious,eog,evince,file-roller,gedit,totem,heif-gdk-pixbuf
 Description: This is the SecureDrop workstation SecureDrop Viewer Disposable VM template configuration package. This package provides dependencies and configuration for the Qubes SecureDrop workstation sd-viewer Template VM.
 Provides: securedrop-workstation-svs-disp
 Conflicts: securedrop-workstation-svs-disp

workstation-config/mimeapps.list.sd-viewer

@@ -28,6 +28,8 @@ image/tiff=org.gnome.Evince.desktop
 image/png=org.gnome.eog.desktop
 image/svg+xml=org.gnome.eog.desktop
 image/vnd.djvu=org.gnome.Evince.desktop
+image/heif=org.gnome.eog.desktop
+image/avif=org.gnome.eog.desktop
 application/vnd.rar=org.gnome.FileRoller.desktop
 application/zip=org.gnome.FileRoller.desktop
 application/x-7z-compressed=org.gnome.FileRoller.desktop