caching issues regarding the preview pages.

[MortenHofft]

          We also have caching issues regarding the preview pages.

I have tested both the local production build and demo.gbif-dev.org against the graphql.gbif-dev.org API.

The preview works on both client and server-side rendered pages in the local build, but only on client-side rendered pages on demo.gbif-dev.org. This leads me to believe that the problem is the caching of server-side rendered pages on demo.gbif-dev.org. Server-side rendered pages should not be cached if the preview=true query parameter is available in the URL of the request.

Originally posted by @danielvdm2000 in #474 (comment)