Regenerate screenshot for preview (in Open Graph XML) programatically so the screenshot is relatively up to date

[corneliusroemer]

@fhennig pointed out our link preview screenshot is out of date. We currently use a hardcoded screenshot that hasn't been updated since launch (for PPX at least).

It would be nice (but low priority/urgency) to generate such a preview programatically, then we could keep it up to date automatically.

This is what I mean by screenshot preview:

It's sourced from this:

<meta property="og:image" content="fully_qualified_image_url_here" />

Slack discussion: https://loculus.slack.com/archives/C05FBAZEFPD/p1740409101911699

[theosanderson]

We could also just not show stats here, it was a relatively arbitrary choice of what to have as the image. I'm not sure I would be in favour of trying to do this programmatically when for example, we already have 5 pathogens so it would be harder to fit them on here, and we may have more at some stage.