Enable mypy as pixi task

[deltamarnix]

Issue addressed

Start implementation for #797

Explanation

Add the possibility to run mypy. Not yet automated in github actions, should be part of pixi run lint. Also adds mypy to workspace recommendations for vs code

General Checklist

• [ ] Updated tests or added new tests
• [ ] Branch is up to date with main
• [ ] Tests & pre-commit hooks pass
• [ ] Updated documentation
• [ ] Updated changelog.rst

Data/Catalog checklist

• [x] data/catalogs/predefined_catalogs.yml has not been modified.
• [x] None of the old data_catalog.yml files have been chagned
• [x] data/chagnelog.rst has been updated
• [x] new file uses LF line endings (done automatically if you used update_versions.py)
• [x] New file has been tested locally
• [x] Tests have been added using the new file in the test suite

Additional Notes (optional)

Add any additional notes or information that may be helpful.

[deltamarnix]

Current status:

630 errors in code unkown number of errors in tests