new 2D advection diffusion example

[slayoo]

TODO:

• [ ] share simulation setting between Trixi.jl and PyMPDATA (e.g., through a common JSON file created in the notebook)
• [ ] save Julia simulation output to a file
• [ ] compare simulation output
• [ ] add Colab/Mybinder badges to the notebook header cell (as in other example notebooks in the repo)

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 92.02%. Comparing base (efc4440) to head (76532e5). Report is 2 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #427 +/- ## ======================================= Coverage 92.02% 92.02% ======================================= Files 30 30 Lines 1468 1468 ======================================= Hits 1351 1351 Misses 117 117 ```

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[slayoo]

@Kojec1 @pawelmagnu the matplotlib version issue is now fixed in the main branch, so I've just rebased this PR's branch accordingly

[slayoo]

kudos @pawelmagnu for making it ✅

[pawelmagnu]

@slayoo examples on windows still time out after 3 re-run, could you help with that?

[slayoo]

@slayoo examples on windows still time out after 3 re-run, could you help with that?

let's see if these will help: #452, #451

[slayoo]

closing & reopening to see if build against current main (with #452 merged) works