Particle packing

[LasNikas]

based on #439 and #436

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 52.32274% with 195 lines in your changes missing coverage. Please review.

Project coverage is 68.75%. Comparing base (7c537a3) to head (9e84053). Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
src/preprocessing/particle_packing/system.jl	0.00%	117 Missing :warning:
src/general/initial_condition.jl	7.69%	24 Missing :warning:
src/preprocessing/particle_packing/rhs.jl	0.00%	18 Missing :warning:
src/setups/complex_shape.jl	38.88%	11 Missing :warning:
src/preprocessing/geometries/io.jl	0.00%	9 Missing :warning:
.../preprocessing/particle_packing/signed_distance.jl	94.61%	7 Missing :warning:
src/callbacks/update.jl	0.00%	2 Missing :warning:
src/preprocessing/geometries/geometries.jl	92.30%	2 Missing :warning:
test/preprocessing/packing/signed_distance.jl	33.33%	2 Missing :warning:
src/general/custom_quantities.jl	0.00%	1 Missing :warning:
... and 2 more

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #529      +/-   ##
==========================================
- Coverage   69.88%   68.75%   -1.14%     
==========================================
  Files          87       93       +6     
  Lines        5476     5840     +364     
==========================================
+ Hits         3827     4015     +188     
- Misses       1649     1825     +176     

Flag	Coverage Δ
unit	68.75% <52.32%> (-1.14%)	:arrow_down:

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[svchb]

Can you please fix the tests first?

[svchb]

@LasNikas Please fix the tests first than I will review this PR.

[svchb]

Please add some tests.

[LasNikas]

~~needs https://github.com/trixi-framework/PointNeighbors.jl/pull/17~~