Warn if there is more than one primary process association

[stephanpelikan]

This causes an unpredictable process to start:

@WorkflowService(workflowAggregateClass.class = MyAggregate.class)
public class FirstWorkflow {
    @Autowired
    private ProcessService<MyAggregate> processService;

    public void start() {
         processService.startWorkflow(new MyAggregate()); // <-- this might start process "SecondWorkflow"
    }
}

@WorkflowService(workflowAggregateClass.class = MyAggregate.class)
public class SecondWorkflow { ... }

This behavior is because there are two primary workflows associated with the aggregate class. The correct annotations are

@WorkflowService(workflowAggregateClass.class = MyAggregate.class)
public class FirstWorkflow { ... }

@WorkflowService(
        workflowAggregateClass.class = MyAggregate.class,
        bpmnProcess = @BpmnProcess(bpmnProcessId = "FirstWorkflow"),
        secondaryBpmnProcesses = { @BpmnProcess(bpmnProcessId = "SecondWorkflow") })
public class SecondWorkflow { ... }

On wiring VanillaBP should detect thus wrong annotations and hint the developer to fix this.