Implement the way to run posix simulator directly from IDE without the need to reconfigure command lines, but use runner created via CMake

Steps to debug:
 * Run gazebo (or any other sim) server and client viewers via the terminal: `make posix_sitl_default gazebo_none_ide`
 * In your IDE select `px4_<mode>` target you want to debug (e.g. `px4_iris`)
 * Start debug session directly from IDE

This approach significantly reduces the debug cycle time because simulator (e.g. gazebo) is always running in background and you only re-run px4 process which is very light.

src/platforms/posix/main.cpp

@@ -286,7 +286,13 @@ static void set_cpu_scaling()
 #endif
 }
 
+#ifdef __PX4_SITL_MAIN_OVERRIDE
+int SITL_MAIN(int argc, char **argv);
+
+int SITL_MAIN(int argc, char **argv)
+#else
 int main(int argc, char **argv)
+#endif
 {
 	bool daemon_mode = false;
 	bool chroot_on = false;