[FEAT] Bring back old animations

[aleksasiriski]

Before we had nice animations for loading results and images, these were easy to implement since we use response streaming and faked a minimum delay. Because we want to support no-JS users, we cannot use response streaming. The animations should be brought back and only be displayed if the user has JS and is doing a new search on the current page.

In addition to that, each image should have it's own little animation while lazy loading, if it's possible.