Altrios flat route demo

[sakhtar312]

Added the flat route demo in altrios. User can select and change variables including:

• Configuration of the rail vehicle (slipstream vs single vehicle
• Number of rail vehicles in slipstream configuration
• Gap size between cars in slipstream configuration
• Number and type of locomotives
• Type of rail vehicle
• Train speed

Based on the inputs above the demo simulates the train operation and calculates resistances (aerodynamic, rolling, bearing) and tractive power. The demo also plots timeseries of variables indicated afore.

[sakhtar312]

@calbaker I have changed the demo to adhere to the new rail vehicle/ train config requirements and the checks pass. Could you review quickly and merge this into main?