feat: add hero image processing and API for serving variants

- Introduced a new script `prepare-hero-variants.mjs` to generate responsive hero image variants in WebP format.
- Added a fallback image `hero_fallback.png` for each variant.
- Created an API endpoint `hero-images.get.js` to retrieve available hero image variants and their fallback images.
- Implemented directory and file checks to ensure the existence of required images before serving.

nuxt.config.js

@@ -77,20 +77,6 @@ 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: '' },
         {