Spring-ai [WIP] Introduce a new evaluator to detect hallucinations

See https://ollama.com/blog/reduce-hallucinations-with-bespoke-minicheck

Comment From: markpollack

I quite like this, i've done a bit of research on the topic and changed the name to FactCheckingEvaluator and added some javadoc. I will write some docs as well with code samples. Thanks.

merged in a987e0305a01e951992964f15096f4eecb800cc2