Extend model.proto to host all classes used in the model

Request Summary

Extend model.proto to host a list of all Agent classes used in the model including their programming language and import path.

Use case

Allow FAME-Core to access classes explicitly and distinguish their programming languages.

Implementation suggestion

Adjust model.proto as follows:

message ModelData {
  message JavaPackages {
    repeated string agents = 1;
    repeated string data_items = 2;
    repeated string portables = 3;
  }

  enum ImplementationLanguage {
    Java = 0;
    Python = 1;
  }

  message AgentClass {
    required string name_alias = 1;
    required string import_identifier = 2;
    required ImplementationLanguage language = 3;
  }

  optional string name = 1;
  optional string version = 2;
  optional JavaPackages package_definition = 3;
  repeated AgentClass agent_classes = 4;
}