Scheduled cleanup without the need to be triggered through API

[mcweba]

The current implementation requires a POST call through the API to clean expired resources.

router.postWithRegex(".*_cleanup").handler(this::cleanup);

It would be practical when vertex-rest storage could clean itself. This would also reduce the complexity of systems using vertx-rest-storge (like gateleen).

The cleanup could be configured with an interval and the amount of resources to clean (already implemented)