PKL to generate conformance and configurations

[xibz]

With PKL we can make our tests and configurations much more maintainable using a language like PKL. This issue will outline some ideas on how we can do so:

1. Must create CDEvent related test models
2. Figure out if we still want to adhere to jsonschema
   a. If we stick with jsonschema for conformance tests, no changes will be needed for the SDKs
3. Document how to use and generate with PKL