Adding pre-commit including flake8&black tests mm
also re-added a date test that still fails (as it should!) added the style check to gitlab-ci
this includes all edits proposed by the style checking (or syntax checking maybe better word).
note in the .pre-commit-config.toml there are a few errors/warnings that are ignored by flake8 because I did not feel like manually fix those yet. You can take them back on and fix one by one..