RMI configuration

Currently, if multiple RMI Servers need to be used, one has to edit the respective ip and port in the code and recompile the project.

To make it more dynamic please provide a server list in the config.properties file. Per server it should include the ip, the port.

At instantiation of a new vehicle, the server should ask the rmi server instance whether it has available resources for another vehicle for the type of model needed (e.g. "Autopilot"). For now , the rmi server should repond with yes and provide a model if it has currently zero assigned vehicles. Otherwise it would say no.