Merge: Serialization: change annotation to `serialize` and intro `noserialize`

Merge: Serialization: change annotation to `serialize` and intro `noserialize`

The annotation `serialize` replaces `auto_serialize` and it is also more versatile. It can annotate a module so all its class definitions are serializable. It can also annotate an attribute so only this attribute is serialized.

The `noserialize` annotation is for exceptions to `serialize`. The most common case is to mark as non-serializable an attribute such as a password or a data blob.

Pull-Request: #1389
Reviewed-by: Alexandre Terrasa <alexandre@moz-code.org>
Reviewed-by: Jean Privat <jean@pryen.org>
Reviewed-by: Lucas Bajolet <r4pass@hotmail.com>