Add example scripts on noisy machine learning with both KerasLayer and TorchLayer

[refraction-ray]

Task description

Add noisy_qml_layer.py in /examples.

Implementation

Mainly for demonstrating tc.KerasLayer()({"state":, "noise":}) and tc.TorchLayer()(state, noise) using Monte Carlo noise simulation with randomness given by the secondary input

Requirements

★★★