add visualisation of threading domain decomposition to cartesian scenario quick_look (incl. README animations)

[slayoo]

No description provided.

[slayoo]

this is how it looks:

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 25.00000% with 18 lines in your changes are missing coverage. Please review.

Project coverage is 68.92%. Comparing base (f0c3589) to head (8eb3391).

Files	Patch %	Lines
scenarios/cartesian.py	20.00%	16 Missing ⚠️
.../local/contract_tests/test_single_vs_multi_node.py	33.33%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #110      +/-   ##
==========================================
- Coverage   71.14%   68.92%   -2.23%     
==========================================
  Files          20       20              
  Lines         454      473      +19     
==========================================
+ Hits          323      326       +3     
- Misses        131      147      +16     

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[slayoo]

let's merge to be able to see the animations in the README, and then let's later discuss how to refactor the quick_look code