Move some notebooks to tutorials repository

[MatteoRobbiati]

I think the tutorials repository could be a nice place where to delve deeper into details of topics (e.g. in the case of the well documented DBI module) in form of notebooks.

I just opened a PR there: https://github.com/qiboteam/tutorials/pulls.
If someone else would prefer to take care of this feel, free to do it. Otherwise we can proceed like I suggested.

I would suggest to leave here at least the intro notebook and the readme file for completeness.

Checklist:

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

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 99.84%. Comparing base (ad50a20) to head (d882820).
Report is 69 commits behind head on master.

Additional details and impacted files

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##           master    #1349   +/-   ##
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  Coverage   99.84%   99.84%           
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  Files          74       74           
  Lines       10806    10806           
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  Hits        10789    10789           
  Misses         17       17           

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unittests	99.84% <ø> (ø)

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[marekgluza]

@MatteoRobbiati I would leave it to @andrea-pasquale to decide - we were aiming to document the module using notebooks.

We could move them for now and then later pull them in but @andrea-pasquale moving them will not break the current docs?

[andrea-pasquale]

Thanks @MatteoRobbiati, also the documentation needs to be updated propertly by removing the links to those notebooks.