box: introduce tuple:info()

See the doc bot request for the description.

Part of #6762

NO_CHANGELOG=next commit

@TarantoolBot document
Title: Document `tuple:info()`
Product: Tarantool
Since: 3.0
Root document: https://www.tarantool.io/en/doc/latest/reference/reference_lua/box_tuple/

tuple_object:info() - Get information about the tuple

Returns a table with the following fields:

 * data_size - Size of the MessagePack data in the tuple.
   This number equals to number returned by `tuple_object:bsize()`.
 * header_size - Size of the internal tuple header.
 * field_map_size - Size of the field map.
   Field map is used to speed up access to indexed fields of the tuple.
 * waste_size - The amount of excess memory used to store the tuple
   in mempool.
 * arena - Type of the arena where the tuple is allocated.
   Possible values are: "memtx", "malloc", "runtime".