only show apps with "What's New" in Latest and Last Updated sidebar

The sidebar is meant to call attention to apps that have been updated recently, so at the very least, they should describe what is new. "What's New" is also is a simple marker that means generally the app is including other metadata like screenshots or localization.

I tried implementing the same rules as fdroidclient!805 (merged) / fdroid-website!398 (merged), but my Liquid scripting skills are weak, and Liquid scripting is weird.