feat: rewrite to Next.js v13 app directory

Improvements:
- Hide switch theme input (ugly little white square)
- i18n without subpath (e.g: /fr or /en), same url whatever the locale used

components/Portfolio/index.tsx

@@ -1,18 +1,15 @@
-import useTranslation from 'next-translate/useTranslation'
+import { getI18n } from '@/i18n/i18n.server'
 
 import type { PortfolioItemProps } from './PortfolioItem'
 import { PortfolioItem } from './PortfolioItem'
 
 export const Portfolio: React.FC = () => {
-  const { t } = useTranslation('home')
+  const i18n = getI18n()
 
-  const items: PortfolioItemProps[] = t(
-    'home:portfolio.items',
-    {},
-    {
-      returnObjects: true
-    }
-  )
+  let items = i18n.translate<PortfolioItemProps[]>('home.portfolio.items')
+  if (!Array.isArray(items)) {
+    items = []
+  }
 
   return (
     <div className='flex w-full flex-wrap justify-center px-3'>