Camel-Cron connector: We need to add at least camel-quartz as dependency

Otherwise we have 

`Caused by: org.apache.camel.FailedToCreateRouteException: Failed to create route route1: Route(route1)[From[cron:cron-timer?schedule=0/5+*+*+*+*+?] -... because of Failed to resolve endpoint: cron://cron-timer?schedule=0/5+*+*+*+*+? due to: Cannot find any CamelCronService: please add a valid implementation, such as 'camel-quartz', in order to use the 'camel-cron' component`
