Add pre-commit (with safety check) and reformat code

Closes #53 (closed)

Description

This MR adds the pre-commit hooks, including the safety pre-commit hook. It also makes sure it runs on GitLab as a pipeline job. Running flake8 has been moved to pre-commit and removed from tox.

I ran pre-commit run --all-files to trigger reformatting the code with black and isort.

Checks

• Running tox and all tests passed
• Running pre-commit run --all-files and all checks passed