feat: OpenHands harness + SWE gym training environment

[athreesh]

Use cases, pain points, and background Openhands is well support in SkyRL as an environment. Will there be an Openhands environment in NemoGym? Looking to train a coding agent on a specific task within an Openhands environment.

Description: Create an openhands environment similar to what SkyRL did. https://github.com/NovaSky-AI/SkyRL-OpenHands

Design: What files should be touched? What logic should be written?

Out of scope: What are some items that this issue could be mistaken to cover that this issue should explicitly NOT cover?

Acceptance Criteria:

• [ ] Individual items that need to be finished in order for this issue to be considered completed