Average surface and volume derived quantities in Cylindrical and Spherical

[jhdark]

Proposed changes

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Types of changes

What types of changes does your code introduce to FESTIM?

• [ ] Bugfix (non-breaking change which fixes an issue)
• [x] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [ ] Code refactoring
• [ ] Documentation Update (if none of the other choices apply)
• [ ] New tests

Checklist

• [ ] Black formatted
• [ ] Unit tests pass locally with my changes
• [ ] I have added tests that prove my fix is effective or that my feature works
• [ ] I have added necessary documentation (if appropriate)

Further comments

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[codecov[bot]]

Codecov Report

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

Project coverage is 99.27%. Comparing base (8d6857b) to head (10fc3b0). Report is 67 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #820      +/-   ##
==========================================
- Coverage   99.27%   99.27%   -0.01%     
==========================================
  Files          60       60              
  Lines        2753     2744       -9     
==========================================
- Hits         2733     2724       -9     
  Misses         20       20              

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