Explore replacing `utilities::error_print()` with `spdlog::error()`

[thanasipantazides]

Why

We need to implement error logging (to file, rather than to console) for the flight. Consider using spdlog for this.

Questions

• What setup (file opening, pointer passing, etc) is needed?
• Any downsides to this library? How does it compare to just appending to a file?