SchedulerPollConsumer - Allow to configure scheduler to use eg camel-quartz for scheduling the task

The org.apache.camel.impl.ScheduledPollConsumer which file/ftp and other scheduled consumer is based upon is using the scheduled thread pool to run the task at X given interval.

It would be great to allow to plugin a different scheduler to be used, for example camel-quartz with a cron expression. This allows more advanced configuration of the scheduler when it should run.