Create helper methods to create groovy SPIN JSON variables and Java Maps that can be inserted into Process Starts and other areas

```groovy
import static org.camunda.spin.Spin.*;

....

      def json = JSON("{\"customer\": \"Kermit\"}")
      def variableMap = ['myJSON':json]

      def processInstance = runtimeService().startProcessInstanceByKey("myProcess", variableMap)
```