Add pre-commit YAML formatter

**Describe the Feature**
When running with a YAML extension enabled it will often auto-format whole files on save, which can be annoying (see #236 for fallout from this behavior). However, having consistent format standards for our various YAML files would be nice. These should be automated, ideally via a pre-commit hook that just runs the formatter, making it easy for everything to be maintained properly without individual developers having to deal with it.