Add __str__ methods to Pydantic models to allow for config printouts

[darthtrevino]

[darthtrevino]

@jgbradley1 you can print out a configuration with the --dry-run CLI option, and it is JSON-structured, not Pydantic focused. Is this issue still relevant?

[jgbradley1]

This is still relevant. The --dry-run option is only useful for end users interacting with graphrag through the CLI interface. It still leaves developers that use the API interface of the package with a challenge of being able to easily track, log, and understand what their workflows look like. If __str__ methods were added, the --dry-run CLI option could be cleaned up to leverage these methods as well to print out the workflows.