add option to output all errors when initializing a structure, instead of failing fast

[loyada]

The use case is when another service makes a call to a strongly typed (typedpy) API. Sometimes it is advantagous to return a list of all the errors, especially when using standard_readable_error_for_typedpy_exception() function.

[loyada]

This should also be implemented in the deserializer to be useful (construct_fields_map function)

[loyada]

done