Fully implement music app and service

SystemTask can return a reference to the nimbleController
The nimbleController can return a reference to the musicService
The musicService get a connection handle from the nimbleController
The musicApp communicated directly with the musicService

src/SystemTask/SystemTask.cpp

@@ -12,6 +12,7 @@
 #include <host/util/util.h>
 #include <drivers/InternalFlash.h>
 #include "../main.h"
+#include "Components/Ble/NimbleController.h"
 
 using namespace Pinetime::System;