Add Quantum Bayesian Inference

[proeseler]

What should we add?

Is there any ongoing work on Quantum Bayesian Inference?

Otherwise, I am currently working on a framework for quantum Bayesian inference and would like to include it soon.

The framework is based on:
https://www.sciencedirect.com
https://journals.aps.org

[edoaltamura]

This implementation was merged in #717.

[edoaltamura]

Closing this issue.