It has been replaced by BjbNotebook

Also derive BijiNoteObj from BjbItem and replace
BijiNoteObj APIs with BjbItem APIs

So that the container won't grow as the content grow

Which will be used for listing notes in the sidebar

This is an exact copy from GTK4 adapted to build without
other dependencies

This has been used already in various projects like gnome-music,
gnome-calls, phosh, etc.

This will help ease porting to GTK4 once we are ready

Also, gtk_window_set_position() has been removed as it's not supported
in GTK4

Get toplevel such that the code also works with GTK4
so as to ease porting

Set GtkImage such that the code also works with GTK4
so as to ease porting

Set GtkImage such that the code also works with GTK4
so as to ease porting

Get toplevel such that the code also works with GTK4
so as to ease porting