Implemented phase 4 for the POC prototype in the Website service.

Services/Website/Sources/App/Extensions/ConfigReader+Properties.swift

@@ -264,6 +264,14 @@ package extension ConfigReader {
         )
     }
 
+    /// The origin passkeys are bound to, read from the `passkeys.origin` key.
+    var passkeysOrigin: String {
+        string(
+            forKey: .Passkeys.origin,
+            default: .Passkeys.origin
+        )
+    }
+
     /// The directory the static files are served from, read from the `path.staticFiles` key.
     var staticFilesPath: String {
         string(