Adding test cases for reading of fourier coefficient file

[kko27]

Adds a test case that reads in Fourier coefficients for boundary condition and fixes the read io bug.

Current situation

Resolves #418 (indexing issue when reading in Fourier coefficient files)

Release Notes

• Added pipe_RCR_3d_fourier_coeff test case
• Test case includes python script fft_temporal_values.py that can convert the .flow file into a .fcs (fourier coefficients) file
• Added unit test (test_fft) that tests the fft function
• Fixed the indexing issue when reading in .fcs files

Documentation

Code is documented with comments. Test case includes an updated README.

Testing

Test case is included as pipe_RCR_3d_fourier_coeff. Unit test has also been included.

Code of Conduct & Contributing Guidelines

• I agree to follow the Code of Conduct and Contributing Guidelines.

[codecov]

Codecov Report

❌ Patch coverage is 93.02326% with 3 lines in your changes missing coverage. Please review.
✅ Project coverage is 67.07%. Comparing base (045220a) to head (0df4ddc).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
Code/Source/solver/read_files.cpp	50.00%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #427      +/-   ##
==========================================
+ Coverage   66.90%   67.07%   +0.17%     
==========================================
  Files         165      166       +1     
  Lines       33711    33746      +35     
  Branches     5672     5673       +1     
==========================================
+ Hits        22553    22636      +83     
+ Misses      11020    10972      -48     
  Partials      138      138              

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[aabrown100-git]

Nice job with this! Just added a few suggestions and questions for clarification.

[ktbolt]

@aabrown100-git Having a script in a test directory means that it does something else than just testing the solver.

The Python script is indeed useful so let's put it someplace users can find it ! I can add documentation for a utilities directory.

[aabrown100-git]

Looks great, love the extensive documentation!

[kko27]

@ktbolt, can we merge or did you want to review it one last time?

[ktbolt]

Very nice documentation I agree !