Feature/manga migration (#536)

* Add "migration" tab to "Browse" screen

* Add missing useEffect cleanup for navbar title and actions

* Make "SourceGridLayout" reusable

* Add migration tab to "Browse"

* Add migration logic

src/screens/Updates.tsx

@@ -104,8 +104,12 @@ export const Updates: React.FC = () => {
 
     useEffect(() => {
         setTitle(t('updates.title'));
-
         setAction(<UpdateChecker />);
+
+        return () => {
+            setTitle('');
+            setAction(null);
+        };
     }, [t, lastUpdateTimestamp]);
 
     const downloadForChapter = (chapter: TChapter) => {