Spring-ai feat: add pg hybridSearch

https://github.com/spring-projects/spring-ai/issues/579

Comment From: impactCn

@markpollack hi,I implemented a hybrid search for PG, using similar search + full-text search.

This is sql for full text search.

SELECT *, ts_rank_cd(to_tsvector(content), plainto_tsquery(?)) AS rank FROM vectorTableName ORDER BY rank DESC LIMIT ?