Added Gemini & X.AI Support, Command Mode, and File Operations

[lecheel]

1. Integration with multiple LLMs: Support was added for both the Gemini and X.AI large language models, allowing users to interact with these AI services.
2. Command Mode and File Operations: A new "command mode" was implemented, enabling users to perform actions like loading messages from files, saving responses, clearing the chat history, and quitting the application using commands (e.g., :o, :w, :clear, :save, :quit). and a fixed 'm' command.
3. Screenshots for Command Mode: Visual aids (screenshots) were added to demonstrate the newly implemented command mode features.
4. Configuration and Output Files The Chat struct now takes a config, and there is support for writing output to file. The handling LLM was refactored to support the output file.

[pythops]

Thanks for the PR :pray: Would you mind break it down to multiple PRs instead, one for each backend and a separate one for the command just to make it easy to review ?

[lecheel]

yes breaking down changes into multiple PRs completed.