feat: Allow us to add own models in LLM Toolkit for OpenAI

[wifiuk]

Is there an existing feature or issue for this?

• I have searched the existing issues

Expected feature

To be able to add the version of model that we want to use rather than being stuck with the ones listed in there now for OpenAI. I'd like to use gpt-4o-mini but there isn't an option to add it or chose from the others I have API access to.

Alternative solutions

No response

Anything else?

No response

[github-actions]

Hey @wifiuk! 🚀 Thanks for this exciting feature idea!

We love seeing fresh concepts that could take reNgine to the next level. 🌟

To help us understand your vision better, could you:

📝 Provide a detailed description of the feature
🎯 Explain the problem it solves or the value it adds
💡 Share any implementation ideas you might have

Your input is invaluable in shaping the future of reNgine. Let's innovate together! 💪