Robust mapping-tester plotting

[fsimonis]

Main changes of this PR

This PR changes the mapping-tester plotting by

• migrating to polars
• refactoring the whole code
• making it more robust
  • it ignores plots for missing columns which happens when only measuring runtime
  • it only uses a log axis if it is numerical
• adding runtime-accuracy plots

The plotting will now work for the current mapping tester examples even though the meshes are not made for this use-case.
We would have to rename them to using element size and adding at least two meshes as 'mesh A'.

Author's checklist

• I used the pre-commit hook and used pre-commit run --all to apply all available hooks.
• I added a test to cover the proposed changes in our test suite.
• I updated the documentation in docs/README.md.
• I added a changelog entry in ./changelog-entries/ (create if necessary).
• I updated potential breaking changes in the tutorial precice/tutorials/aste-turbine.

[davidscn]

Do we still have the (optional) plotting of comparison slopes of a specific order? e.g. second order curve?

[fsimonis]

I noticed that the slopes have been disabled quite some time ago. IIRC they needed so much manual fine-tuning, that it was easier to hack them into the final output then integrate it into the script itself.