Implement RC calibration, common for the real drone and the simulation

gazebo/SBUS.h

@@ -0,0 +1,13 @@
+// Copyright (c) 2023 Oleg Kalachev <okalachev@gmail.com>
+// Repository: https://github.com/okalachev/flix
+
+// SBUS library mock to make it possible to compile simulator with rc.ino
+
+#include "joystick.h"
+
+class SBUS {
+public:
+	SBUS(HardwareSerial& bus) {};
+	void begin() {};
+	bool read(int16_t* channels, bool* failsafe, bool* lostFrame) { joystickGet(); return true; }; // NOTE: on the hardware channels is uint16_t
+};