Add support for sequence unrolling in flipping and flipping_signal

[Jacfomg]

It adds support for sequence unrolling in flipping and flipping_signal as requested in qiboteam/qibolab_platforms_qrc#119. It has only been tested with dummy.

Checklist:

• Reviewers confirm new code works as expected.
• Tests are passing.
• Coverage does not decrease.
• Documentation is updated.
• Compatibility with Qibo modules (Please edit this section if the current pull request is not compatible with the following branches).
  • Qibo: master
  • Qibolab: main
  • Qibolab_platforms_qrc: main

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (b11efdd) 97.23% compared to head (b4a1dc4) 97.24%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #720      +/-   ##
==========================================
+ Coverage   97.23%   97.24%   +0.01%     
==========================================
  Files         110      110              
  Lines        7618     7646      +28     
==========================================
+ Hits         7407     7435      +28     
  Misses        211      211              

Flag	Coverage Δ
unittests	97.24% <100.00%> (+0.01%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files	Coverage Δ
src/qibocal/protocols/characterization/flipping.py	96.89% <100.00%> (+0.43%)	⬆️
...ocal/protocols/characterization/flipping_signal.py	97.32% <100.00%> (+0.32%)	⬆️
src/qibocal/protocols/characterization/ramsey.py	100.00% <ø> (ø)

[igres26]

Seems to work as expected in the tries made with quantum machines. Albeit the speed-up in that case is not very significant, it is still there.

[andrea-pasquale]

I've not tested the PR on hardware, but the code seems to be fine.

[andrea-pasquale]

Maybe one quick thing, could you add also tests with the option unrolling=True?
If you do also coverage should pass.