Hyperoptimizing with Optuna

[MatteoRobbiati]

Moving from Hyperopt to Optuna, which is more maintained.

Checklist:

• [ ] Reviewers confirm new code works as expected.
• [ ] Tests are passing.
• [ ] Coverage does not decrease.
• [ ] Documentation is updated.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 97.10%. Comparing base (434989e) to head (0f9e4e2). Report is 44 commits behind head on master.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #1338 +/- ## ======================================= Coverage 97.10% 97.10% ======================================= Files 81 81 Lines 11653 11653 ======================================= Hits 11316 11316 Misses 337 337 ``` | [Flag](https://app.codecov.io/gh/qiboteam/qibo/pull/1338/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=qiboteam) | Coverage Δ | | |---|---|---| | [unittests](https://app.codecov.io/gh/qiboteam/qibo/pull/1338/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=qiboteam) | `97.10% <100.00%> (ø)` | | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=qiboteam#carryforward-flags-in-the-pull-request-comment) to find out more.

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[andrea-pasquale]

Thanks @MatteoRobbiati, given that #1269 was just merged probably we need to update this PR. Eventually me or @Sam-XiaoyueLi could take care of merging main. Let me know.

[MatteoRobbiati]

The coverage here suffers the same problem we are fixing in #1438. What concerns Hyperopt -> Optuna should be ready to be reviewed @andrea-pasquale @Edoardo-Pedicillo @Sam-XiaoyueLi.

[scarrazza]

@MatteoRobbiati could you please fix the conflict?

[MatteoRobbiati]

@MatteoRobbiati could you please fix the conflict?

Done!