feat: preload common fonts

[ojeytonwilliams]

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Without this, some fonts either do not render initially or a fallback is rendered briefly.

Before, using 'Fast 3G' to slow down the load:

and after:

It's most noticeable in the search results, but also some bold and italic text is initially not rendered until the font loads.

I also tried out gatsby-plugin-preload-fonts, but it took about an hour to create the cache and puppeteer apparently did not try to search as the search specific fonts were not preloaded.

This could be improved if we know for sure that some fonts are not universal (Roboto Mono Italics perhaps) as they can be added only on the pages they appear.

Closes #37311

[gitpod-io]