Support passing nested structures as tuples

[akudiyar]

Currently, nested structures may be passed only as maps (despite whether the structure is a simple object or an entity). This may be not efficient in case if the structures are merged as a result of a map-reduce operation resembling a "join", especially in the case of collections of structures, since it requires using "tomap" operation on each tuple corresponding to a nested structure.

We need to provide a way for deserializing nested structures from tuples.

Possible solution:

Allow specifying the serialized source type for the object fields that contain nested structures with some kind of annotation (e.g. @Field(serialize = TarantoolSerializationType.TUPLE))