Add LATS and Reflexion

[kargarisaac]

Is your feature request related to a problem? Please describe.
I use the CodeAgent in my work and am amazed by its performance. It is mainly based on ReAct. However, I feel it is more than that, but still, there are some limitations. One of the things that I am missing is the revision step. The other thing is the search (like MCTS) capability and the ability to generate multiple chains of thoughts. I want to start building some of the more advanced agents like LATS and Reflexion.

Describe the solution you'd like
I want to add some agents with the revision and MCTS capability like LATS and Reflexion.

Is this not possible with the current options.
I think with some improvements, it is possible to have these new agents. I am thinking of some new classes for these agents inherited from CodeAgent with more functionality or changing the logic and workflow.

Describe alternatives you've considered
I have found llamaindex and langgraph implementations of these new agents:
https://github.com/langchain-ai/langgraph/blob/main/docs/docs/tutorials/lats/lats.ipynb
https://docs.llamaindex.ai/en/stable/examples/agent/lats_agent/
https://langchain-ai.github.io/langgraph/tutorials/reflexion/reflexion/