Use a Cache Wrapper Struct instead of DataCache inside of ConnWrapper

[Heiss]

So the user can define, what he wants to use. If it is needed, the CacheWrapper should Wrap the the conn and stores the returned data. The user can decide, if the data should be updated or comes from the cache. This ease the usage.

Find a way to store the returned data. Maybe something with Deref and DerefMut.

For a performance boost, the user can decide, when the cache should be updated. Example: The user locks the data and updates the cache at the beginning and can now operate on the cached data locally, knows he holds the lock.
At the first implementation, it should push all changes to cached data immediality to redis.
Later it should be possible to cache the changes and push them all at once (with redis transactions!). This comes with the downside, that if you lose the lock, because of sleep, you do not have any changes at all. So the user must decide, what is needed. This could be different CacheWrapper