[pre-commit](https://pre-commit.com/) is a framework for easy set-up
of pre-commit hooks.
This adds configuration for it to run:
* ts compilation
* ts linting
* pr-checks synchronization
The latter required the `sync.py` to be callable from the project root.
`pre-commit` can be enabled with
```
python3 -m pip install pre-commit
pre-commit install
```
