Implement utility transcript loader

[paulbricman]

In debategpt.inference.core, the Debate class is designed for orchestrating the generation and study of a debate. For instance, there are the d.play() and d.step() methods which help run the debate forward.

However, we'll have fully fleshed out transcripts for comparing ArgRank outputs to other computational argumentation approaches and human verdicts.

The task is to create a utility method of the Debate class which takes in a transcript and updates the object state accordingly (e.g. curr_round), so that one can then call d.graph and obtain the argument graph associated with the transcript. Might want to consult with Elfia about the structure of the transcripts, so as to facilitate their loading.

[paulbricman]

Here's Elfia's data source (for figuring out how to parse the transcripts into a more structured representation): https://docs.google.com/document/d/1VpX7VN0TXCtjcL1jrYNUEBA6affIGukmPpspjKHQKh0/edit?usp=sharing

[paulbricman]

Closed by #2