Remove preview-link if functionality is disabled

[orbitbot]

To my understanding, as of the issue with flems previews being misused, the preview functionality has been indefinitely disabled. However, the UI still contains an icon and a link to give the impression this might be an issue with the current site functionality, which currently leads to an NGINX 404 page.

If the functionality is not going to be reinstated it would be better to remove it. Removing the element from the UI might be valid even if it will be possible to do at some point in the future.

The original issue might be possible to handle with f.e. an enforced splash screen of some kind, perhaps?