[Sync] Apollo cache persist should have configurable debug parameter

[wtrocki]

There is no simple way to see persisted objects in cache. Adding debug flag is possible but currently, there is no way to do it without recompiling distribution binary.

[darahayes]

I think ultimately it would make sense to have accept a client options object and also a cache options object to allow for more flexible configuration.

We could allow users to supply an object satisfying the ApolloPersistOptions interface https://github.com/apollographql/apollo-cache-persist/blob/master/src/types/index.ts#L19-L28 and merge that with some sensible defaults. What do you think?

[wtrocki]

There are two approaches here. We can allow people to modify how the client is created since currently, we hide tons of options from Apollo client inside our wrapper.
For example, it is not possible to use @Local resolvers in our client as this requires passing custom code to client. Historically we started with something called client builder, but now I think that we may need to simply have a way to build our "uber" link and allow people to create client with their options. To simplify things createClient can still stay, but we should be probably exposing our default link instance (we do not at the moment). This will give users full upstream api that they can interact with + draw line what our client provides: "An opinionated link chain for offline and conflict resolution".

There will be many flags like this that clients will need to poke with and currently the only one way will be to simply fork the project which is not ideal.