Introduce `aria-label` for links

For screenreader accessibility. Example from https://dequeuniversity.com/rules/axe/4.7/link-name

```html
 <a href="taxhike.html" aria-label="Read more about Seminole tax hike">[Read more...]</a>
```

Issue flagged via [google lighthouse ](https://pagespeed.web.dev/analysis/https-www-borgbackup-org/7v84jokimt?form_factor=mobile)