Configuration validation #79
Description
Generic concepts such as uniqueness of entry name should be enforced by reaktor and nukleus-specific options or when clauses should be validated either via delegation to the nukleus or by checking against a nukleus-provided JSON schema.
The JSON-schema approach is preferred because it is declarative and can be used to verify specification project configuration independent of implementation.
Therefore the reaktor-generic aspects of configuration should also be described by JSON schema if possible, to let the full configuration be validated from specification projects.