Thrown a Runtime Error on config Fail

[ndmmdn]

If the U-blox is not correctly configured, it is logged as FATAL, but the node does not crash/exit. This leads to a 'zombie node' running and prevents handling of this error outside the node itself.

I added a runtime_error to this condition, so the node actually dies. This can then be handled via the 'restart=True' parameter in a ros2 launch file.