Added a CLI command to update layout. (#521)

globals.d.ts

@@ -7,6 +7,7 @@ declare global {
     var useTheme: (filePath: string) => void;
     var getSystrayItems: () => string;
     var isWindowVisible: (windowName: string) => boolean;
+    var setLayout: (layout: string) => string;
     var clearAllNotifications: () => Promise<void>;
     var setWallpaper: (filePath: string) => void;