Implemented the SampleAppParameters type in the sample app target, and integrated it to the SampleApp type.

Samples/DocCMiddleware/SampleApp.swift

@@ -0,0 +1,24 @@
+// ===----------------------------------------------------------------------===
+//
+// This source file is part of the Hummingbird DocC Middleware open source project
+//
+// Copyright (c) 2025 Röck+Cöde VoF. and the Hummingbird DocC Middleware project authors
+// Licensed under the EUPL 1.2 or later.
+//
+// See LICENSE for license information
+// See CONTRIBUTORS for the list of Hummingbird DocC Middleware project authors
+//
+// ===----------------------------------------------------------------------===
+
+import struct ArgumentParser.OptionGroup
+
+/// A type that implements and runs the sample executable that showcases the `Hummingbird-DocC` middleware.
+@main struct SampleApp {
+    
+    // MARK: Properties
+    
+    /// A type that contains all the necessary input parameters to run the sample executable.
+    @OptionGroup var parameters: Parameters
+
+}
+