Simplify Adapter#serialize by using snapshot.serialize() since they d…

[bmac]

…uplicate the same logic

cc @wecc

[sly7-7]

After a quick search about adapter.serialize, it seems like it's never called in the repository. Maybe we could even deprecate it and remove it for 3.0 ?

[bmac]

That sounds good to me @sly7-7. I think the same thing could happen for store#serialize

[sly7-7]

@bmac I just wonder what we want as a public api for serializing a record. Do we want only keep record.serialize(options) ?
Nevermind, store.serialize is private, so I guess we can simply remove that one (even without deprecation)

[bmac]

I think record.serialize(options) and snapshot.serialize(options) is the way to go.