Add a notebook explaining various paradigms of QML

[saum-g]

Summary

Added a notebook explaining implementation and inspiration of VQE, VQA, QAOA and hybrid NN

Details and comments

The notebook first discusses a basic VQE example. Then proceeds to discuss implementing VQE on LiH. After generalising VQE to VQA, it discusses QAOA implementation and implementation on NISQ hardware. Finally, it discusses hybrid NN and inspiration for them. The notebook takes a lot of code from the qiskit textbook and tries to explain things in a gradual manner

[CLAassistant]

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