Combine type serialization properties into one export

[critesjosh]

Consider adding SERIALIZED_LEN to the TypeSerializationInterface to make the imports in contracts less verbose.

For example,

global FIELD_SERIALIZED_LEN: Field = 1;

could be added to

global FieldSerializationMethods = TypeSerializationInterface {
    deserialize: deserializeField,
    serialize: serializeField,
};

@Maddiaa0 correct me if I'm wrong, but this was my takeaway from the call.

[rahul-kothari]

Am hoping that Traits removes the need for this altogether!