- Remove polymorphic base, this only existed because TKMM has a desktop/switch setup prodecure difference and has 2 implementations of the setup wizard. We only need one.
- Remove Systems/UI file split, they're all in Ryujinx.Ava.UI now
- made NotificationHelper instance-based to allow you to encapsulate notifications to a window that magically disappear when the window is closed, instead of switching to showing on the main window.
renamed view models to contexts (like TKMM), however the contexts here are actually of a unique base type; containing aforementioned setup step logic. if the return value is of an error state result, it will prompt a retry of the page.
