Implement C API entry points for creating and fetching non-standard types to OrtValue (#1714)

C/C++ Opage APIs
 Add new virtual interfaces for NonTensorType
 Implement entry points.
 Add shared header for the data container.
 Add export symbols.
 Add serialization/deserialization.
 Implement model with Opaque types.
 Rework opqaue_api_test as a standalone executable.