JCLOUDS-750 Revert customizing FieldNamingStrategy in favor of tighter contract on @SerializedNames.

In  5b6f1e9, we added the ability to customize the FieldNamingStrategy, so that you can control the serialized names on auto-value types. I've added code to propagate the same names used for deserialization to also be used for serialization. With this in, customizing FieldNamingStrategy is no longer needed, and should be removed.
[minor] Should we also update the Javadoc for `constructor` in this case? Also, if there is going to be a follow-up to this, rename to something like `constructorsOrFactories`?