virtio-devices, vmm: add I/O rate limiter on block device

This patch is based on the 'rate_limiter' module from firecracker[1]. To
simplify dependencies, we reply on 'vmm-sys-util::TimerFd' instead of
the `timerfd` crate.

[1]https://github.com/firecracker-microvm/firecracker/tree/master/src/rate_limiter

Fixes: #1285

Signed-off-by: Bo Chen <chen.bo@intel.com>

vmm/src/device_manager.rs

@@ -1943,6 +1943,7 @@ impl DeviceManager {
                     disk_cfg.num_queues,
                     disk_cfg.queue_size,
                     self.seccomp_action.clone(),
+                    disk_cfg.rate_limiter_config,
                 )
                 .map_err(DeviceManagerError::CreateVirtioBlock)?,
             ));