Update ApplyPmmlModelCommand to manage both PMML implementations

Currently, ApplyPmmlModelCommand (inside drools) invoke directly the legacy PMML delegate (ApplyPmmlModelCommandExecutorImpl).

1. move Command newApplyPmmlModel(PMMLRequestData request); from ExtendedKieCommands to KieCommands
2. define PMMLCommandExecutor interface inside kie-internal (droolsjbpm-knowledge)
3. define PMMLCommandExecutorFactory interface inside kie-internal (droolsjbpm-knowledge)
4. write PMMLCommandExecutor implementation (inside kie-pmml-trusty )
5. write PMMLCommandExecutorFactory implementation (inside kie-pmml-trusty )
6. write kie.konf in the same module as PMMLCommandExecutorFactory implementation to bind the implementation to the interface
7. create a static method "isToEnable()" to be used by PMMLAssemblerService(s) and ApplyPmmlModelCommand to retrieve which implementation is to be enabled - it will replace the ones in PMMLAssemblerService(s) (inside kie-api)
8. modify ApplyPmmlModelCommand to switch between factories/implementations (using the above method to choose the implementation to enable)