Write a validator that can validate the format of test bundles, so that user know if they have an error in their yaml files. Selection of validators: - [Pydantic](https://pydantic-docs.helpmanual.io/) bigger, needs more time to learn - [JSONSchema](https://github.com/Julian/jsonschema) bigger, needs more time to learn - [Cerberus](https://docs.python-cerberus.org/en/stable/) leight-weight and small