Added Melody Struct & Ajusted MQTT Subs and Deserialization

A new Melody Struct was added containing the melody's main attributes.
The MQTT Topic Subscriptions were updated to a more proper format.
Also added DEV_ID that corresponds to the device's ID or Serial Number.
Chnaged the Deserialization function to actually adjust the MelodyStruct's attributes.
Added basic play/stop functionality.

functions.hpp

@@ -0,0 +1,71 @@
+#pragma once
+
+extern volatile bool playing;
+
+
+void playback(JsonDocument doc){
+	if (doc["playback"].as<bool>()){
+		playing = true;
+		Serial.println("START Playback!");
+	}
+else if (doc["playback"].as<bool>()){ 
+		playing = false;
+		Serial.println("STOP Playback!");
+	}
+}
+
+void selectMelody(JsonDocument doc){
+	
+	melody.name = doc["name"].as<const char*>();      // Convert to std::string
+	melody.id = doc["id"].as<uint16_t>();
+	melody.duration = doc["duration"].as<uint32_t>();
+	melody.infinite_play = doc["infinite"].as<bool>();
+	melody.interval_duration = doc["inter_dur"].as<uint16_t>();
+	melody.speed = doc["speed"].as<uint8_t>();
+
+	Serial.printf("Name: %s, ID: %d, Duration: %lu, Inf: %s, Inter: %d, Speed: %d\n", 
+		melody.name.c_str(), 
+		melody.id, 
+		melody.duration, 
+		melody.infinite_play ? "true" : "false", 
+		melody.interval_duration, 
+		melody.speed);	
+		
+}
+
+void handleJSON(String payload) {
+	
+	JsonDocument doc;
+	DeserializationError error = deserializeJson(doc, payload);
+	
+	if (error) {
+		Serial.print("deserializeJson() failed: ");
+		Serial.println(error.c_str());
+		return;
+	}
+	
+	selectMelody(doc);
+	playback(doc);
+	
+}
+
+
+
+
+
+
+
+
+/*
+possible topics: 
+
+vesper/client-id/control
+	/play
+	/stop
+
+vesper/client-id/select_melody
+	
+vesper/client-id/update_melody
+
+vesper/client-id/add_melody
+*/