Added Xiao S3 variant.

This is for Xiao S3 and a normal Wio SX1262 for Xiao shield.

variants/xiao_s3/XiaoS3Board.h

@@ -0,0 +1,13 @@
+#pragma once
+
+#include <Arduino.h>
+#include <helpers/ESP32Board.h>
+
+class XiaoS3Board : public ESP32Board {
+public:
+  XiaoS3Board() { }
+
+  const char* getManufacturerName() const override {
+    return "Xiao S3";
+  }
+};