MetaData for Caching/Read/Write etc

[chrisjenx]

Right now we only store the entities and when they were added, I think a meta data style table which can store last read/write to the table, maybe last accessed key etc. This will help with caching or stale data to know when a client would want to delete/refresh/use cached data etc.

• Last Read/Write for the entity in question
• Last Entity ID to be read/written (dunno how useful this would be?)
• Support Async/Sync writing to metadata