refactor: Refactor DevExpressSwissQrCodeProcessor to use Codecrete QRBill parser

- Change return type to tuple (Bill, string[])
- Remove custom parsing methods (ParseSwissQrBillContent, MapAddress, DetermineReferenceType)
- Use Codecrete QRBill.DecodeQrCodeText() for parsing
- Add SkiaSharp.QrCode v1.0.0 for QR decoding
- Remove obsolete ZXing and System.Drawing dependencies
- Add StringExtensions for QR code detection
- Raw lines properly split and trimmed from QR text

DocumentOperator.Infrastructure/Services/StringExtensions.cs

@@ -0,0 +1,16 @@
+using System.Xml.Serialization;
+
+namespace DocumentOperator.Infrastructure.Services;
+
+public static class StringExtensions
+{
+    public static T? DeserializeXml<T>(this string xmlText)
+    {
+        if (string.IsNullOrWhiteSpace(xmlText))
+            return default;
+
+        var serializer = new XmlSerializer(typeof(T));
+        using var reader = new StringReader(xmlText);
+        return (T?)serializer.Deserialize(reader);
+    }
+}