Extract dayjs setup into file

src/index.tsx

@@ -8,20 +8,12 @@
 
 import { StrictMode } from 'react';
 import { createRoot } from 'react-dom/client';
-import dayjs from 'dayjs';
-import customParseFormat from 'dayjs/plugin/customParseFormat';
 import { App } from '@/App';
 import '@/index.css';
 // roboto font
 import '@fontsource/roboto';
 import { defaultPromiseErrorHandler } from '@/util/defaultPromiseErrorHandler.ts';
-import { loadDayJsLocale } from '@/util/language.tsx';
+import '@/lib/dayjs/Setup.ts';
-
-dayjs.extend(customParseFormat);
-
-loadDayJsLocale(navigator.language).then(() => {
-    dayjs.locale(navigator.language);
-});
 
 if ('serviceWorker' in navigator) {
     navigator.serviceWorker.ready.then((registration) => {

src/lib/dayjs/Setup.ts

@@ -0,0 +1,17 @@
+/*
+ * Copyright (C) Contributors to the Suwayomi project
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+import dayjs from 'dayjs';
+import customParseFormat from 'dayjs/plugin/customParseFormat';
+import { loadDayJsLocale } from '@/util/language.tsx';
+
+dayjs.extend(customParseFormat);
+
+loadDayJsLocale(navigator.language).then(() => {
+    dayjs.locale(navigator.language);
+});