A widget for showing a Avatar (a.k. Pixbuf) or generate a fallback avatar. The fallback is based on https://gitlab.gnome.org/GNOME/Initiatives/issues/6
- We probably want the new style https://gitlab.gnome.org/Teams/Design/os-mockups/issues/47
- Fix: The icon (fallback when no name is given) is black.
- Better name for the "name" property (GtkWidget has already a "name" property): maybe "text"?
- Works on HIDPI