Improving the documentation/usability around Redis caching and extensions

[Turnerj]

From https://github.com/TurnerSoftware/CacheTower/issues/163#issuecomment-824140978

I think from this perspective adding the Redis setup examples would be good. The RedisLockExtension has RedisLockOptions and it isn't clear from a first glance what the configurable options are for. Also, with this RedisRemoteEvictionExtension I think it needs to be made clear that the layers you want to evict from will not be Redis in general.

This aspect would be important to improve to help make onboarding to Cache Tower easier.

[Turnerj]

This will be better covered when a roll out of a website for the library is completed.