virtio-devices: seccomp: Add seccomp_filter module

This patch added the seccomp_filter module to the virtio-devices crate
by taking reference code from the vmm crate. This patch also adds
allowed-list for the virtio-block worker thread.

Partially fixes: #925

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

virtio-devices/src/epoll_helper.rs

@@ -25,6 +25,7 @@ pub enum EpollHelperError {
     CreateFd(std::io::Error),
     Ctl(std::io::Error),
     Wait(std::io::Error),
+    ApplySeccompFilter(seccomp::Error),
 }
 
 pub const EPOLL_HELPER_EVENT_PAUSE: u16 = 0;