Refactor subcell_limiting_kernel! => volume_integral_kernel!

[DanielDoehring]

Following #2754 #2802 #2812

[github-actions]

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 97.12%. Comparing base (8a91650) to head (a17bec5).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2821   +/-   ##
=======================================
  Coverage   97.12%   97.12%           
=======================================
  Files         593      593           
  Lines       45686    45680    -6     
=======================================
- Hits        44369    44364    -5     
+ Misses       1317     1316    -1     

Flag	Coverage Δ
unittests	97.12% <100.00%> (+<0.01%)	⬆️

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