Automatically load an exeriment/settings set on startup

[OlgerSiebinga]

Is your feature request related to a problem? Please describe.
Testing the system with the same setup (e.g., one ego vehicle on spawn point x, controlled by a USB controller) can be annoying because you have to set the setting at every boot.

Describe the solution you'd like
Add an argument to the main script to automatically load an experiment file on startup, this will replace the default settings.

Describe alternatives you've considered
There was a default settings option, but this was deprecated because it caused problems with another new feature.