Fix some performance issues

* Remove render blocking stripe JS that seems unnecessary
* Use native lazy loading of images
  - Truly a progressive enhancement, only affects browsers that support it
  - Causes a warning: [Intervention] An <img> element was lazyloaded with loading=lazy, but had no dimensions specified. Specifying dimensions improves performance. See https://crbug.com/954323, which can not be easily fixed
* Render content first, hydrate after that

components/Footer.tsx

@@ -14,6 +14,7 @@ const SponsorLink = ({ href, name }: Props) => (
       src={`/static/images/sponsors/${name.toLowerCase()}.svg`}
       alt={name}
       className={`sponsor sponsor__${name.toLowerCase()}`}
+      loading="lazy"
     />
   </a>
 );