Provide a way to list all the models currently supported by the Copilot CLI

### Describe the feature or problem you'd like to solve

Provide a way to list all the models currently supported by the Copilot CLI

### Proposed solution

I wish there is a way to list all the models including multiplier info currently offered by the Copilot CLI.

```sh
copilot --list-models
```

or

```sh
copilot help models
```

### Example prompts or workflows

N/A

### Additional context

_No response_