feat: add robots.txt and sitemap.xml routes for SEO optimization

- Implemented a new route for robots.txt to control crawler access.
- Added a sitemap.xml route to provide search engines with a list of site URLs.
- Included functions for URL normalization and XML escaping to ensure proper formatting.

nuxt.config.js

@@ -77,6 +77,20 @@ export default defineNuxtConfig({
       ],
       link: [
         { rel: 'canonical', href: 'https://www.harheimertc.de/' },
+        {
+          rel: 'preload',
+          as: 'image',
+          href: '/images/club_about_us_hero_960.webp',
+          type: 'image/webp',
+          media: '(max-width: 1024px)'
+        },
+        {
+          rel: 'preload',
+          as: 'image',
+          href: '/images/club_about_us_hero_1600.webp',
+          type: 'image/webp',
+          media: '(min-width: 1025px)'
+        },
         { rel: 'preconnect', href: 'https://fonts.googleapis.com' },
         { rel: 'preconnect', href: 'https://fonts.gstatic.com', crossorigin: '' },
         {