GPT-4 Only Option

[keenborder786]

Background

There was no option that allowed the model to run in GPT-4 only mode.

Changes

Changed main.py module. parse_argument function was modified and the gpt4only argument was added to the parser. If gpt4only is provided by the user then fast_llm_model is set to smart_llm_model just like vice versa is happening in gpt3only mode.

Documentation

No additional documentation was needed.

Test Plan

PR Quality Checklist

• My pull request is atomic and focuses on a single change.
• I have thouroughly tested my changes with multiple different prompts.
• I have considered potential risks and mitigations for my changes.
• I have documented my changes clearly and comprehensively.
• I have not snuck in any "extra" small tweaks changes

[keenborder786]

@Torantulino please have a look.

[keenborder786]

Please let me know if this is the correct way to go about it or do you want me to make any more changes to make gpt4only mode. I tested it and it seem to be working. Thank you.

[nponeccop]

LGTM but @Torantulino will inspect the logic