feat: add redisearch vectorstore (#1307)
# Description
Add `RediSearch` vectorstore for LangChain
RediSearch: [RediSearch quick
start](https://redis.io/docs/stack/search/quick_start/)
# How to use
```
from langchain.vectorstores.redisearch import RediSearch
rds = RediSearch.from_documents(docs, embeddings,redisearch_url="redis://localhost:6379")
```
