feat: Add LangChain4j Agentic Planner implemetation

[ricardozanini]

What would you like to be added:
Currently, we have implemented the workflow API from langchain4j-agentic module. They are evolving their API now to the "Planner" concept. See: langchain4j/langchain4j#3929

Why is this needed:
To align our experimental/agentic-langchain4j module to the upstream workflow API.

[ricardozanini]

Feature moved away from the SDK since we removed LC4J integration. More here: https://github.com/quarkiverse/quarkus-flow/tree/main?tab=readme-ov-file#langchain4j-choose-your-approach