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_utils.cpp

@@ -1,5 +1,5 @@
-#include <math.h>
 #include "az_utils.h"
+#include <math.h>
 
 AzUtils::AzUtils() {}