without this change we can't have a contract that will generate a stub but not a test. Of course that's for a reason since it's overriding the very essence of contract test.
with this change we assume that the users know what they're doing and that they will use this flag rarerly. Cause it means that you can have a false positive.
related to gh-881
* Rewritting to java
- rewritten a lot of Spring Cloud Contract Spec module to Java
- extracted all Groovy stuff to a separate package
- will now continue writing extension modules
- spring-cloud-contract-spec will be written purely in java
- spring-cloud-contract-spec-groovy will have Groovy extensions
fixes gh-1130
