Show name of command vehicle acting as a simulated region

[lukasrad02]

In a real incident, command personnel might not identify themselves with the name of their region but rather the name of their vehicle on radio.

Therefore, the name of the command vehicle (after #870 is implemented) or the name of the vehicle the currently assigned leader belongs to should be shown in the component of the assign leader behavior. The vehicle name should also be shown in the title of radiograms so the interface signaller can decide whether they announce their role as the name of the region or the vehicle.