Entry API shouldn't require NamedCollection

[ecton]

Currently the only way to utilize the entry API is if you implement NamedCollection. This was done to make it so that the entry API can take an ID or the "name" key. We should offer a way to use an entry API via SerializedCollection that only allows the primary key.

This will cause conflicts with the NamedCollection API. I'm not sure if there's any way to unify the API without specialization, so most likely we should rename NamedCollection's entry API.