[SEO] Add structured data

• Richer results when searched through search engine
• Help search engine understand purpose of our website

BTW what type we gonna use? I guess at least we should use the "Breadcrumb" one.

Yes, we can start with the Breadcrumb one and refer to wargabantuwarga.com's implementation

Once we implement and deploy it to production, we can preview it with the Rich Results Test.

References:

• https://developers.google.com/search/docs/advanced/structured-data/search-gallery