Add ExtractSwissQrCode feature and update feature order

Updated PHASENPLAN.md and ROADMAP.md to reflect the new
feature order, making "ExtractSwissQrCode" Feature 2 and
renumbering previous Features 2-5 to 3-6. Added detailed
steps, endpoints, and acceptance criteria for the new
feature.

Implemented `ISwissQrCodeProcessor` interface with
`DevExpressSwissQrCodeProcessor` for extracting and parsing
Swiss QR Codes using DevExpress and Codecrete libraries.
Registered the new service in DependencyInjection.cs.

Introduced `SwissQrCodeData` value object and
`SwissQrCodeNotFoundException` for domain modeling and
error handling. Updated project dependencies to include
libraries for QR code processing.

Adjusted existing feature descriptions and steps to align
with the new feature order.

DocumentOperator.Domain/Exceptions/SwissQrCodeNotFoundException.cs

@@ -0,0 +1,22 @@
+namespace DocumentOperator.Domain.Exceptions;
+
+/// <summary>
+/// Exception thrown when a Swiss QR Code cannot be found in a PDF document.
+/// </summary>
+public sealed class SwissQrCodeNotFoundException : Exception
+{
+    public SwissQrCodeNotFoundException()
+        : base("No Swiss QR Code found on the last page of the PDF document.")
+    {
+    }
+
+    public SwissQrCodeNotFoundException(string message)
+        : base(message)
+    {
+    }
+
+    public SwissQrCodeNotFoundException(string message, Exception innerException)
+        : base(message, innerException)
+    {
+    }
+}