Reapply "Add missing admin action files and navigation links"

This reverts commit 4d515bc400.

src/app/admin/translations/cms/page.tsx

@@ -0,0 +1,11 @@
+import fs from 'node:fs/promises'
+import path from 'node:path'
+import { TranslationsClient } from '../translations-client'
+
+export default async function CmsTranslationsPage() {
+  const messagesDir = path.join(process.cwd(), 'messages')
+  const enContent = await fs.readFile(path.join(messagesDir, 'en.json'), 'utf-8')
+  const itContent = await fs.readFile(path.join(messagesDir, 'it.json'), 'utf-8')
+
+  return <TranslationsClient enJson={enContent} itJson={itContent} />
+}