Maintenance task for the filebucket

As per:

• https://groups.google.com/forum/#!topic/puppet-users/GjTxlD7VRww/discussion
• https://ask.puppetlabs.com/question/132/does-filebucket-need-periodic-maintenance-cleaning/

Sometimes it's useful to clean the clientbucket on a Puppet master as it can grow over time and after a while becomes useless. It would be nice if there's a rake task / maintenance task within Puppet that takes care of it instead of having to resort to a cron calling find and deleting everything older than $criteria.