Integration of EVIDEN's GraphCast

[colon3ltocard]

• Wait for #2 and @cbovalo greenlight
• Write Settings class
• Write Torch nn.Module subclass
• Add model to CI/CD

[cbovalo]

@colon3ltocard it's up to you :)

[A669015]

The EVIDEN version of Graphcast is now available at https://github.com/AI4SIM/meteo_france