Introduce cruft to keep the repository up to date with template changes

[Kircheneer]

• Introduce cruft
• Replace pytest-redislite with pytest-redis as a consequence unit tests needs to be run in Docker or redis needs to be installed locally (fixes #139 and enable Docker buildx to function)

Why is this not in the CI (already)? I wasn't sure about including it because that would mean that updates to the cookiecutter template would cause this CI to somewhat arbitrarily fail, we should follow up at a later point, maybe post diffs to slack if there are any?