glib: Add PopplerPoint boxed type

https://bugs.freedesktop.org/show_bug.cgi?id=70981
glib: Add support for simple line annotations

https://bugs.freedesktop.org/show_bug.cgi?id=70981
glib-demo: add color selection for new annotations

https://bugs.freedesktop.org/show_bug.cgi?id=71727
glib-demo: Add support for simple line annotations

https://bugs.freedesktop.org/show_bug.cgi?id=70981