Add capability to write volume slices

[anilyil]

Purpose

This PR adds the capability to write surface solutions of volume slices. The slices are defined by externally provided surfaces similar to the user integration surfaces.

Expected time until merged

Type of change

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (non-backwards-compatible fix or feature)
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no API changes)
• Documentation update
• Maintenance update
• Other (please describe)

Testing

Checklist

• I have run flake8 and black to make sure the Python code adheres to PEP-8 and is consistently formatted
• I have formatted the Fortran code with fprettify or C/C++ code with clang-format as applicable
• I have run unit and regression tests which pass locally with my changes
• I have added new tests that prove my fix is effective or that my feature works
• I have added necessary documentation

[codecov]

Codecov Report

Attention: Patch coverage is 26.92308% with 19 lines in your changes missing coverage. Please review.

Project coverage is 41.01%. Comparing base (4ef1799) to head (e24cc18).

Files with missing lines	Patch %	Lines
adflow/pyADflow.py	26.92%	19 Missing ⚠️

❌ Your patch check has failed because the patch coverage (26.92%) is below the target coverage (50.00%). You can increase the patch coverage or adjust the target coverage.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #382      +/-   ##
==========================================
- Coverage   41.19%   41.01%   -0.18%     
==========================================
  Files          13       13              
  Lines        4127     4147      +20     
==========================================
+ Hits         1700     1701       +1     
- Misses       2427     2446      +19     

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