[MachineLearning.Inference] Add Inference APIs for Machine Learning (#940)

[MachineLearning.Inference] Add Inference APIs for Machine Learning (#940)

* [MachineLearning] Add TensorsInfo and TensorsData class

This patch newly adds the TensorsInfo and TensorsData class for C# API.

Signed-off-by: Sangjung Woo <sangjung.woo@samsung.com>
* [MachineLearning] Add SingleShot class for inference

This patch newly adds the SingleShot class for C# API.

Signed-off-by: Sangjung Woo <sangjung.woo@samsung.com>
* [MachineLearning] Add testcase for MachineLearning API

This patch newly adds the test applicaion for MachineLearning API, which
is based on NNStreamer.

Signed-off-by: Sangjung Woo <sangjung.woo@samsung.com>
* [MachineLearning] Update the feature key and exception in public method

This patch newly adds the related feature key and exceptions into public
methods. It does not change the code except XML comments.

Signed-off-by: Sangjung Woo <sangjung.woo@samsung.com>