Add ReactiveRedisTemplate, add tests abd add SerializerFunction and DeserializerFunction for functional Redis argument serialization.
Introduce ReactiveRedisConnectionFactory and remove reactive RedisConnectionFactory methods to break the dependency to reactive types. We now no longer require Project Reactor for blocking Redis use. ReactiveRedisTemplate accepts ReactiveRedisConnectionFactory to operate on a reactive connection. The only implementation of ReactiveRedisConnectionFactory is LettuceConnectionFactory which requires by default Project Reactor.
Original Pull Request: #239
81657c530b