Improve use of MAVSDK::add_any_connection()

Added error printing and possibility to use UART as connection
to the flight controller.

Issue: https://denyspopov.atlassian.net/browse/AZ-16
Type: New Feature

src/az_mission_controller.cpp

@@ -2,11 +2,10 @@
 
 #include <mavsdk/plugins/telemetry/telemetry.h>
 
-#include "az_mission_controller.h"
 #include "az_mission.h"
+#include "az_mission_controller.h"
 #include "az_utils.h"
 
-
 AzMissionController::AzMissionController(AzMission &mission, QObject *parent)
     : QObject(parent)
     , mMission(mission)