Introduce an alternative autoconfiguration if the lettuce Redis driver is
available. Add Lettuce-specific configuration property options
"spring.redis.lettuce.shutdown-timeout" to control the shutdown timeout
of the lettuce driver. Add documentation for the properties, the
supported drivers, and how to switch between drivers.
Split client-specific properties from spring.redis.pool to
spring.redis.jedis.pool and introduce spring.redis.lettuce namespace.
Deprecate spring.redis.pool property.
See gh-5311