Add custom QZ Tray fork with pairing key authentication

- Custom fork of QZ Tray 2.2.x with certificate validation bypassed
- Implemented pairing key (HMAC) authentication as replacement
- Modified files: PrintSocketClient.java (certificate check disabled)
- New files: PairingAuth.java, PairingConfigDialog.java
- Excluded build artifacts (out/, lib/javafx*) from repository
- Library JARs included for dependency management

tray/src/qz/exception/NullCommandException.java

@@ -0,0 +1,10 @@
+package qz.exception;
+
+public class NullCommandException extends javax.print.PrintException {
+    public NullCommandException() {
+        super();
+    }
+    public NullCommandException(String msg) {
+        super(msg);
+    }
+}