Did this so that models can be updated more often fixing bugs where when a material is set as "not favorite" in the favorites section, its updated accordingly in its "normal" section.
It's also the ground work for saving material section expansion to preferences.
Contributes to CURA-5378
I was hoping to completely nix the generic materials model (since it's basically just a brand "Generic", but then in the QML it has to be have the same in terms of sub-menus or fold-outs and that looked stupid (Generic -> ABS -> ABS)). So we keep that one for now. It is cleaner though.
Contributes to CURA-5162, CURA-5378
