Enstrophy for 2D Navier-Stokes

[DanielDoehring]

This PR extends functionalities existing in 3D to 2D.

[jlchan]

Thanks for adding this!

[codecov]

Codecov Report

Merging #1591 (9b64552) into main (fe0e78c) will increase coverage by 13.08%.
The diff coverage is 53.85%.

@@             Coverage Diff             @@
##             main    #1591       +/-   ##
===========================================
+ Coverage   83.00%   96.07%   +13.08%     
===========================================
  Files         400      401        +1     
  Lines       33019    33088       +69     
===========================================
+ Hits        27405    31789     +4384     
+ Misses       5614     1299     -4315     

Flag	Coverage Δ
unittests	96.07% <53.85%> (+13.08%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files Changed	Coverage Δ
...s/tree_2d_dgsem/elixir_navierstokes_shear_layer.jl	0.00% <0.00%> (ø)
src/callbacks_step/analysis_dg2d.jl	100.00% <100.00%> (+13.33%)	⬆️
src/equations/compressible_navier_stokes_2d.jl	98.17% <100.00%> (+0.13%)	⬆️

... and 71 files with indirect coverage changes

[DanielDoehring]

Hm, the CI MPI test for mac fails when run with coverage, the non-covered version seems to be fine.

[jlchan]

Could be related to #1590

[jlchan]

LGTM. Thanks for adding this functionality!

[ranocha]

Thanks