Add the ability to configure LLMs via the web interface

[changchichung]

Is your feature request related to a problem? Please describe.
No

Describe the solution you'd like

"I've encountered quite a bit of trouble when configuring different LLMs. I frequently see 'invalid API key' errors in the Docker logs, but I've double and triple-checked that the GEMINI/DEEPSEEK/OPENAI API keys I have in my ~/.wrenai/.env file are correct.

I'd like to suggest simplifying these configurations as much as possible, adopting a program setting method similar to Chatbox/AnythingLLM, where there's a web interface to select which LLM to connect to, allowing users to input their API keys or API URLs, and then have a dropdown menu for model selection, similar to this:"

[cyyeh]

let me put this as good first issue. We welcome the community to contribute to this idea. You could discuss with us how you would like to design the solution first. Thank you