This way it's not available to the rest of Cura, especially since PackageList is not such an uncommon name. It could give name collisions. Moreover, the rest of Cura doesn't need to have a list of packages from the Marketplace, so it's better separation.
Contributes to issue CURA-8556.
This has a slight bug in that the icon will immediately change to an arrow once loading has completed, but will slowly rotate back to angle 0. You don't see this, since the new plug-ins will come in between. The new plug-ins will always be a full page, or otherwise the icon disappears altogether and it's not visible anyway. But if you hold down the scrollbar while loading and quickly scroll down when loading completed, you can see this happen. I don't think anyone will really mind though.
Contributes to issue CURA-8556.
To display the background across the entire bottom side and not with the margins of the column, we have to restructure where the margins are a bit.
Contributes to issue CURA-8556.
Currently just a title and a page. The title is separate because in between there will be the tabs selecting which page is shown. The title will also change depending on that, but that'll have to be implemented separately. The page is loaded with a loader to make it efficient, and also to make it extensible when the tabs get implemented in a follow-up ticket.
Contributes to issue CURA-8556.
