Support SSL/TLS in druid-redis-cache

[winsmith]

Description

While the memcached cache provider allows for the druid.cache.enableTls config property, the redis cache provider ignores this flag, even though Jedis does have a ssl flag

Motivation

I would really like to connect to a hosted AWS Elasticache for Redis instance where I can't disable transport encryption

Contributing

I will try to build a PR to implement this

[FrankChen021]

This flag is used for memcache, which is not the default cache in Druid.
But I think we can add such configuration to the redis cache.