Include panoramic top images in Wikivoyage scrapes

[Jaifroid]

These were probably not available in the now-deprecated mobile-sections endpoint (#1664), but I wonder if the solution to that issue might allow us finally to include these panoramic images that appear on most Wikivoyage articles (see screenshot comparing online Wikivoyage with our scrape). Not having these images really detracts from the attractiveness of Wikivoyage articles in ZIMs. In some articles, the top panoramic image is the only image. This is tangentially related to #179 and maybe #1193.