Replace `prettier` pre-commit hook

The `prettier` pre-commit has seemingly been dead for a while now: https://github.com/EnergySystemsModellingLab/MUSE_2.0/issues/581

While it works for now, we probably shouldn't rely on this. Let's move to using other hooks to format JSON and YAML. See example in `python-template` repo: https://github.com/ImperialCollegeLondon/python-template/blob/main/.pre-commit-config.yaml

When I last checked, I couldn't get pre-commit to work in a container using our `Dockerfile`, I think because of some nodejs-related issue. Moving to Python-based hooks might also fix this problem.