Application of tensor-network MBQC simulation

[shinich1]

Add a .py file in example that illustrates the usage and application of TN simulation of MBQC, which contains:

• Detailed, step-by-step description of the TN construction and contraction in tensornetwork backend of graphix, and an example of how to tune the parameters for contraction path finding.
• Illustrate two exemplary applications of TN-based MBQC simulation which involves hundreds or thousands of qubits in the graph. Perhaps one of the following: i) simulation of many-body quantum systems ii) QML, iii) variational algorithm.

Additional context