feat(website): Add more notifications to the Review page

[fhennig]

resolves #2561, resolves #3412

preview URL: https://more-toast.loculus.org

Summary

• Info notifications added on both delete buttons and the release button. (Style of the popups still to be refined)

But I think maybe we don't need this anymore, as deleting and releasing is now very fast? I can't reproduce the 15 second delay, even for 4000 sequences.

IMO I might just close both issues as not relevant anymore.

Screenshot

PR Checklist

• All necessary documentation has been adapted.
• The implemented feature is covered by appropriate, automated tests.
• Any manual testing that has been done is documented (i.e. what exactly was tested?)