- move source file according with platformio standard directory structure

- remove lib_deps from platformio.ini since they are already in libs folder

src/MqttReceiver.h

@@ -0,0 +1,9 @@
+#pragma once
+
+#include <Arduino.h>
+
+class MqttReceiver
+{
+public:
+    virtual void onMqttDataReceived(const char* topic, byte* payload, const unsigned int length) = 0;
+};