add overloaded constructors for RedisCache
Here is the best practice for Azure Cache for Redis: Documentation
To follow the best practice "Configure your client library to use a connect timeout of at least 15 seconds", we would like to set the redisClient connection timeout as 15 seconds.
However, this is a common library which can be used for any provider, and the recommended value of connection timeout may be different. So we consider to have overloaded constructor where ClientOptions can be passed when initialize RedisCache.