entry: Use css nodes for icons
entry: Use css nodes for icons

Create css nodes for icons in entries, with name image, and use
gtk_style_context_save_to_node() for them. We still set the
style classes .left and .right on them.

alexlarsson/gtk,grubersjoe/adwaita,alexlarsson/gtk,alexlarsson/gtk,alexlarsson/gtk,alexlarsson/gtk,grubersjoe/adwaita,alexlarsson/gtk,alexlarsson/gtk,alexlarsson/gtk,grubersjoe/adwaita,grubersjoe/adwaita,grubersjoe/adwaita,grubersjoe/adwaita,grubersjoe/adwaita,grubersjoe/adwaita