Define the State -> Transition definition

Define a basic version of the Transition type based on the Serverless Workflow definition version (https://github.com/serverlessworkflow/specification/blob/main/specification.md#Transitions) and provide a fist implementation (https://github.com/davidesalerno/kogito-serverless-operator/blob/main/api/v1alpha1/kogitoserverlessworkflow_types.go )