Feat/mle bench evaluation

[csmith49]

End-user friendly description of the problem this fixes or functionality that this introduces

• [ ] Include this change in the Release Notes. If checked, you must provide an end-user friendly description for your change below

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Give a summary of what the PR does, explaining any non-trivial design decisions

This PR adds support for testing OpenHands agents on MLE-bench using the standard OpenHands evaluation harness.

The MLE-bench implementation provides:

1. A set of scripts to manage test instances, run benchmarks, and score results.
2. A base Docker image in which agents should be run.
3. An agent definition format.

The goal of this PR is to re-use as much existing infrastructure as possible by providing a suitable OpenHands agent definition. However, only the scripts from 1. are exposed as a Python package, so we assume the tester has OpenAI's implementation installed elsewhere to manage the base image and test instances and need to re-implement some minor scaffolding around agent definitions to allow for benchmarking from this repo.

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Link of any specific issues this addresses

#4328