Add suppliers and shortcuts for the Agentic DSL

[ricardozanini]

What would you like to be added:

Having done #730 for the base spec, now we can start adding the suppliers, consumers, and DSL recipes to the agentic DSL too. As a reference for the DSL, we can use LangChain4j agentic module.

Why is this needed:

The reason is similar to the original issue, but now pursuing the agentic use cases.