Multiagent scenario tasks

[kantneel]

Currently multiagent scenario tasks are not robustly abstracted and only support minimal features. They are identical to tasks in single agent scenarios except for also including agent-specific instructions which are appended to the prompts of the individual agents. While this theoretically allows for directing agents to do pretty much anything, the environment itself only accounts for a single task with its singular parameters and verification criteria.

Full featured multiagent task support would mean each agent has its own task e.g. ThroughputTask and the environment tailors the observations for the agent as directed by the task (stating the goal, enhancing program stdout, etc.). The tasks should probably also get their own force parameter (team/faction in factorio API) so that agents can be formally on other teams if desired.

[kantneel]

Actually the Team abstraction in #206 would be right way to do this. The tasks themselves probably shouldn't have agent-specific instructions. Instead a team config should delegate responsibility and/or set up hierarchy.