Update The World CDN policies to work with Next.js

[rpeterman-gp]

1. Responses should preserve the Vary header value returned by Next.js. See https://nextjs.org/docs/app/guides/cdn-caching#where-cdn-caching-is-challenging
2. The following headers should be passed to origin (See https://nextjs.org/docs/app/guides/cdn-caching#handling-headers-at-the-cdn):
   • next-router-state-tree
   • next-router-segment-prefetch
   • next-url
   • rsc
3. The _rsc search parameter must be included in cache keys.