Structured Data support for the Page protocol in the Infrastructure package (#32)

This PR contains the work done to introduce a `StructuredData` type that pages use to describe themselves to search engines as schema.org JSON-LD, and wires it into the Page protocol so the payload renders automatically in the document head.

Reviewed-on: rock-n-code/loud-amsterdam#32
Co-authored-by: Javier Cicchelli <javier@rock-n-code.com>

Packages/Infrastructure/Tests/Cases/Public/Protocols/PageTests.swift

@@ -97,6 +97,31 @@ struct PageTests {
         #expect(html.contains(#"<meta name="twitter:card" content="summary_large_image">"#))
     }
 
+    @Test
+    func `omits the structured data script by default`() {
+        let html = StubPage().render()
+
+        #expect(!html.contains("application/ld+json"))
+    }
+
+    @Test
+    func `renders the structured data script when provided`() {
+        let html = StubPage(structuredData: .init(
+            name: "Stub Site",
+            url: "https://stub.example/",
+            logo: "https://stub.example/logo.png",
+            profiles: ["https://social.example/stub"]
+        )).render()
+
+        #expect(html.contains(
+            #"<script type="application/ld+json">"# +
+            #"{"@context":"https://schema.org","@graph":["# +
+            #"{"@type":"Organization","@id":"https://stub.example/#organization","name":"Stub Site","url":"https://stub.example/","logo":"https://stub.example/logo.png","sameAs":["https://social.example/stub"]},"# +
+            #"{"@type":"WebSite","name":"Stub Site","url":"https://stub.example/","publisher":{"@id":"https://stub.example/#organization"}}]}"# +
+            #"</script>"#
+        ))
+    }
+
     @Test
     func `appends the version token to the asset URLs`() {
         let html = StubPage(assetVersion: "0123456789abcdef").render()