Add production Greenlight credentials example

snippets/csharp/Production.cs

@@ -0,0 +1,18 @@
+using Breez.Sdk;
+
+public class ProductionSnippets
+{
+    public NodeConfig ProductionNodeConfig() {
+        // ANCHOR: moving-to-production
+        // Read your Greenlight credentials from secure storage
+        var deviceKey = new List<byte>();
+        var deviceCert = new List<byte>();
+        var greenlightCredentials = new GreenlightCredentials(deviceKey, deviceCert);
+        
+        var nodeConfig = new NodeConfig.Greenlight(
+            new GreenlightNodeConfig(greenlightCredentials, null)
+        );
+        // ANCHOR_END: moving-to-production
+        return nodeConfig;
+    }
+}