Trackio logger

Nobody has claimed this yet.

### Description & Motivation

I propose adding a dedicated [Trackio](https://huggingface.co/docs/trackio) logger for PyTorch Lightning. Trackio is a lightweight experiment tracking library that works well for local prototyping and small-scale experiments. Trackio is very easy to work with and hack, lightweight, and is based on Gradio. It is ideal for users who want minimal setup or cannot rely on external services. Trackio's API is meant as a drop-in replacement to WandB's, but I believe that a dedicated Lightning logger might be justifiable as per my understanding implementation details make it kind of cumbersome to re-use the existing WanDB logger. Ofc I'd be happy to discuss more suitable alternatives.

### Pitch

I would like to add a new TrackioLogger class, modeled after the existing WandB logger, that integrates seamlessly with PyTorch Lightning. The implementation would include proper unit tests and documentation, enabling Lightning users to track experiments with Trackio just as they would with other loggers. This would provide a native, lightweight option for local and flexible experiment tracking.

### Alternatives

The closest alternative is running a local WandB server, but this approach is less flexible, especially if customizations are needed to the visualizations/graphics, harder to hack, and requires additional setup (e.g., a Docker container). Trackio offers similar functionality with less overhead, making it a more convenient solution for quick prototyping and lightweight workflows.

### Additional context

_No response_

cc @lantiga

Start by reading the existing WandB logger and the Trackio documentation linked in the issue to understand the integration surface and API differences. Define the TrackioLogger behavior, add the proposed unit tests and documentation, and confirm that Lightning users can track experiments through the new logger.

Written by the indexing model from the issue text.