NOISSUE debranding for real, initial work

This is probably very broken on macOS and Windows and will need a lot of work to complete fully.

launcher/pages/modplatform/atlauncher/AtlPage.h

@@ -21,7 +21,7 @@
 #include <QWidget>
 #include <modplatform/atlauncher/ATLPackInstallTask.h>
 
-#include "MultiMC.h"
+#include "Launcher.h"
 #include "pages/BasePage.h"
 #include "tasks/Task.h"
 
@@ -45,7 +45,7 @@ public:
     }
     virtual QIcon icon() const override
     {
-        return MMC->getThemedIcon("atlauncher");
+        return LAUNCHER->getThemedIcon("atlauncher");
     }
     virtual QString id() const override
     {