<schema object>:map() now supports transforming composite types

[TarantoolBot]

<schema object>:map() now calls the user-provided transformation
function not only on scalar schema nodes, but also on record, map
and array nodes. The function is called on the outmost node first,
then on the descandant ones.

<schema object>:apply_default() now supports the default annotation
(and the apply_default_if one) for composite types. Similarly to
:map() it traverses the nodes in the pre-order way.
Requested by @Totktonada in tarantool/tarantool@d1208ea.