Ref: #2086, nuxt/framework#3544

Smartly prefetch next pages with <NuxtLink>.

Considerations:

• Support payload prefetching for static routes
• Lower priority and disable for slow connections
• Consider using Link Prefetching

References:

• https://developer.mozilla.org/en-US/docs/Web/HTTP/Link_prefetching_FAQ
  Nuxt 2 prefetch: https://github.com/nuxt/nuxt.js/blob/dev/packages/vue-app/template/components/nuxt-link.client.js