Implement CoreML converter

[tucan9389]

Core ML

Requirements

• coremltools? vs tf-coreml?
• https://github.com/apple/coremltools/blob/master/examples/neural_network_inference/tensorflow_converter/Tensorflow_2/tf_keras_fashion_mnist.ipynb

[tucan9389]

• minimum_ios_deployment_target arg can get only ["11.2", "12", "13"].
• but support only "13" on tf.keras model

AttributeError: module 'tensorflow' has no attribute 'reset_default_graph'

→ So maybe our TF2 project is needed to downgrade TF1.x

[tucan9389]

model.save(model_path) only support for Functional model or a Sequential model in kears of TF2 😢