[proposal] Add model name validation

[dkuku]

Is your feature request related to a problem? Please describe.

currently I can provide any model name and it fails when it's not valid after first prompt

Describe the solution you'd like

--list-models option would be useful Also validating if all requirements are set for a model would be useful.

interpreter --model mistral/mistral-tiny-invalid
error: no such model. similar named models are ...
interpreter --model mistral/mistral-tiny
error: no MISTRAL_AI_KEY set ... 

### Describe alternatives you've considered

I'm not sure if this is the repo where it should be implemented or should it be litellm. But lite llm is closer to metal and you need to check their docs - here the model is an command line param and can be easily mistyped

### Additional context

_No response_

[MikeBirdTech]

I like the idea of validation but there are way too many models for a list-model flag.

Maybe there's a possibility for a fuzzy search against popular models to suggest options when one isn't found? I'm sure there are other possibilities too. However, using offline might prove difficult. I'd be interested in hearing more about this.

It would need to be a community contribution as there are other pressing issues to resolve but this could definitely help with usability