New tutorials section

[luisaFelixSalles]

This PR add the tutorials section in the documentation

• Change the user guide index page
• Create the tutorials section/ topics
• Add the jupyter_sphinx extension so the tutorials snippets will be executed when the doc is built

Preview on how it renders:

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 88.02%. Comparing base (f3463cb) to head (97f32dc).
Report is 46 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1876      +/-   ##
==========================================
- Coverage   88.10%   88.02%   -0.08%     
==========================================
  Files          83       83              
  Lines        9951     9963      +12     
==========================================
+ Hits         8767     8770       +3     
- Misses       1184     1193       +9     

---- 🚨 Try these New Features:

• Flaky Tests Detection - Detect and resolve failed and flaky tests