Improve reproducibility of pipeline outputs

[ashsong-nv]

Add fields to the pipeline output that would help improve pipeline reproducibility. This would help with accuracy evaluation and improvement efforts.

Some ideas of fields to add to the output:

• Input config (such as model parameters)
• Pipeline config (such as whether to use the code search tool, whether the QA tool should return source documents)
• Rendered prompts
• Specific git commit hash when the input ref is a tag or branch

[ashsong-nv]

@shawn-davis per discussion today, I've tested that it's possible to get the current checked out commit hash by running git rev-parse HEAD in the cloned repo directory after the checkout step. However, we might need to do some testing to find the equivalent command for doing this in the git python library. We will also need to add a new attribute to the output schema to store this.

Since there are quite a lot of changes needed to improve reproducibility, it would be good to break the tasks above into separate issues/PRs to make the PRs smaller.