feat(website): resize images to max-size used in website

[corneliusroemer]

Add script process_images.sh that allows recompressing in the future if new organisms are added.

Implementing this recommendation from Google's PageSpeedInsights: https://pagespeed.web.dev/analysis/https-pathoplexus-org/gnxkqyl8t4?form_factor=mobile

preview URL: https://smaller-images.loculus.org

Summary

Screenshot

PR Checklist

• [ ] All necessary documentation has been adapted.
• [ ] The implemented feature is covered by an appropriate test.

[theosanderson]

Just to warn you - we probably actually need to host the images elsewhere: #2500

[corneliusroemer]

2500 is orthogonal and this PR here won't break anything afaict, let's separate the discussions? Does something prevent you from approving @theosanderson?