Use Redis cache by default when ICacheClient is undefined

I would think that it's more typical to move from an in-memory cache to a Redis cache. As such wouldn't it be better to use Redis as the default when no cache is explicitly specified? 

If `ICacheClient` is undefined and `IRedisClientsManager` is defined, default to a Redis cache rather than an in-memory cache. 

If somebody needs the two types of cache in a single application, would it not be better that they define the `MemoryCacheClient` explicitly as this use-case should be less prevalent?