Make error norm calculation optional

[DanielDoehring]

The calculation of the error norms is for non MPI runs (i.e., thread-parallel applications) not parallelized and can thus consume a tremendous fraction of computation time for large 2D, 3D systems.
While one might be interested in quantities computed by the analysis_callback such as the integrals of internal and kinetic energy, seldom $L^2$ and $L^\infty$ errors are for practical applications of interest.

Then, the computation of errors can be avoided by passing

analysis_callback = AnalysisCallback(semi, interval=analysis_interval, analysis_errors = Symbol[])

If only extra_analysis_errors are desired, one needs to pass in e.g.

analysis_callback = AnalysisCallback(semi, interval=analysis_interval, analysis_errors = [:conservation_error])

[github-actions]

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (7a7ce48) 96.24% compared to head (32172b0) 96.24%.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1755   +/-   ##
=======================================
  Coverage   96.24%   96.24%           
=======================================
  Files         431      431           
  Lines       34895    34896    +1     
=======================================
+ Hits        33582    33583    +1     
  Misses       1313     1313           

Flag	Coverage Δ
unittests	96.24% <100.00%> (+<0.01%)	⬆️

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[ranocha]

Sounds reasonable to me. Could you please document the new behavior in the docstring at the top of this file?

[ranocha]

Thanks!