Fix/remove deprecated routes (#747)

* Route to "/" in case path is unknown

* Remove deprecated routes

"sources" and "extensions" were merged into "browse" but the routes were never removed, thus, the paths still matched and opened the components

src/screens/SourceMangas.tsx

@@ -225,7 +225,7 @@ export function SourceMangas() {
             clearCache: boolean;
         }>().state ?? {};
 
-    useSetDefaultBackTo('sources');
+    useSetDefaultBackTo('browse');
 
     const [isFirstRender, setIsFirstRender] = useState(true);