Web support for the Website service (#17)

This PR contains the work done to introduce a new Web Swift package that provides a reusable, declarative way to register route controllers on a Hummingbird router, then adopt it in the Website service.

To provide further details about the work:

* Web package
  * The `RouterController` protocol — a Sendable protocol to group controllers behind one `routes` property.
  * The `RouteCollectionBuilder`  — a result builder that collects controllers' route collections into a stack, with full support for optionals, conditionals, and arrays.
  * The `addController(_:)` method — a `RouterMethods` extension letting controllers be listed declaratively and adding each one's routes at the router root.

* Website service
  * Added Web as a dependency of the _WebsiteLibrary_ target.
  * Conformed the `RootController` and `HealthController`controllers to the `RouterController` protocol.
  * Updated the `App+Build` extension to to use the cleaner `router.addController { … }` instead.

Reviewed-on: rock-n-code/loud-amsterdam#17
Co-authored-by: Javier Cicchelli <javier@rock-n-code.com>
Co-committed-by: Javier Cicchelli <javier@rock-n-code.com>

Services/Website/Package.swift

@@ -26,6 +26,9 @@ let package = Package(
         .package(
             path: "../../Packages/Persistence"
         ),
+        .package(
+            path: "../../Packages/Web"
+        ),
         .package(
             url: "https://github.com/elementary-swift/elementary.git",
             from: "0.6.0"
@@ -77,6 +80,7 @@ let package = Package(
             dependencies: [
                 .byName(name: "Localization"),
                 .byName(name: "Persistence"),
+                .byName(name: "Web"),
                 .product(
                     name: "Configuration",
                     package: "swift-configuration"
@@ -115,6 +119,8 @@ let package = Package(
         .testTarget(
             name: "WebsiteLibraryTests",
             dependencies: [
+                .byName(name: "Persistence"),
+                .byName(name: "Web"),
                 .byName(name: "WebsiteLibrary"),
                 .product(
                     name: "Elementary",