feature: GenerationLog support in Colang 2.x

[Pouyanpi]

Did you check the docs?

• I have read all the NeMo-Guardrails docs

Is your feature request related to a problem? Please describe.

Currently Colang 2 does not support some of the nice features of Colang 1.0, specifically it has limited support for GenerationOptions like GenerationLog. This feature is crucial for better observability into various compontnets of a rails instance.

Describe the solution you'd like

Enable GenerationLog in Colang 2.x, it requires implementation of compute_generation_log method similar to its Colang 1.0 counterpart and popoulate the GenerationLog object.

Describe alternatives you've considered

For compatibility the feature needs to be implemented, no alternative available.

Additional context

• add the exact path to implementation here.