Site: Add sitemap

[daneah]

The problem Some systems like search engines and other crawlers like to have a sitemap to exhaustively understand a site's content.

The solution Automatically generate a sitemap using Gatsby at build time.

Alternatives considered

• Manually create a sitemap: higher effort, likely to diverge
• Don't add a sitemap: lose potential value opportunities as the site grows

Additional information The gatsby-plugin-sitemap is a good candidate for use.