Improve regression test maintainability

[janssenhenning]

Here I collect issues that need to be improved for easier maintenance of the regression tests.

• Exclude test data from autoformatting in pre-commit (otherwise some changes will be done leading to lots of noise)
• Exclude more files from calculations
  • struct.xsf
  • band.gnu
  • All the different config files profile.config, etc.
• Normalize out.xml in some way. Maybe we prepare some script that does the normalization which we insert into the append text of the test code
  • Strip out timestamps (?)
  • Strip out compilation/build specific info
  • Only use export_cache or mock-code for one test. mock-code produces a lot of files for workflows so here export_cache is probably the way to go (for now the calculations folder is just put into the gitignore to remove them :))
  • Swallow logs At the moment a lot of logs are emitted for all tests