Add CartesianProductSet to PyROS

[shermanjasonaf]

Summary/Motivation:

This PR adds to PyROS the CartesianProductSet class, a new pre-implemented concrete UncertaintySet subclass for representing a Cartesian product (or cross product) of uncertainty sets. For simplicity, this initial implementation of the CartesianProductSet does not support products involving one or more discrete uncertainty sets; such support will be added in a future PR.

Changes proposed in this PR:

• Add PyROS CartesianProductSet class

Legal Acknowledgement

By contributing to this software project, I have read the contribution guide and agree to the following terms and conditions for my contribution:

1. I agree my contributions are submitted under the BSD license.
2. I represent I am authorized to make the contributions and grant the license. If my employer has rights to intellectual property that includes these contributions, I represent that I have received permission to make contributions and grant the required license on behalf of that employer.

[shermanjasonaf]

@jas-yao @natalieisenberg @jsiirola

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 89.99%. Comparing base (c1ce36d) to head (67b1ccc).
⚠️ Report is 64 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3927      +/-   ##
==========================================
+ Coverage   89.98%   89.99%   +0.01%     
==========================================
  Files         904      904              
  Lines      106891   106969      +78     
==========================================
+ Hits        96191    96272      +81     
+ Misses      10700    10697       -3     

Flag	Coverage Δ
builders	29.14% <26.92%> (-0.01%)	⬇️
default	86.32% <100.00%> (?)
expensive	35.58% <26.92%> (?)
linux	87.46% <100.00%> (-2.02%)	⬇️
linux_other	87.46% <100.00%> (+0.01%)	⬆️
oldsolvers	28.09% <26.92%> (+<0.01%)	⬆️
osx	82.83% <100.00%> (+0.01%)	⬆️
win	85.90% <100.00%> (+0.01%)	⬆️
win_other	85.90% <100.00%> (+0.01%)	⬆️

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[jsiirola]

This looks good. Some minor updates to docstrings if you have time, but (in my opinion) nothing that must prevent merging.