Support for dictionaries as observations?

[CaptainTrojan]

Does LightZero provide support for complex observation types, such as dictionaries of multiple tensors? If not, where should the change be made? Right now I'm thinking:

1. hope that all tensors in the dictionary are of the same type
2. join them and flatten the result
3. let LZero do its thing
4. unflatten the flattened tensor merge inside a custom model implementation (override model class)

[puyuan1996]

In this PR39, we have put the emphasis on managing complex structured observations. The current main branch does not yet provide support for dict-type observations. However, PR39 provides an good reference to devise a specialized encoder for dictionary-type observations. Once developed, this encoder can replace the main backbone of the representation network (as indicated in common.py). Moreover, you might need to make minor adjustments in the data preprocessing code specifically in game_buffer_muzero.py. For guidance, you can refer to the modifications made in this PR39. By incorporating these changes, you can effectively manage more complex structured observation data.

Please note that the modifications in PR39 are intended for handling more intricate structured observations and are for reference only.