refactor: move NetJob away from ModModel to ModAPI

This is done so that 1. ModAPI behaves more like an actual API instead
of just a helper, and 2. Allows for more easily creating other mod
providers that may or may not use network tasks (foreshadowing lol)

launcher/ui/pages/modplatform/modrinth/ModrinthModel.h

@@ -29,8 +29,8 @@ class ListModel : public ModPlatform::ListModel {
     ListModel(ModrinthPage* parent);
     virtual ~ListModel();
 
-   private slots:
-    void searchRequestFinished() override;
+   public slots:
+    void searchRequestFinished(QJsonDocument& doc) override;
 
    private:
     const char** getSorts() const override;