Add a libblkio engine

Add a libblkio engine

The libblkio library provides a unified API for efficiently accessing
block devices using modern high-performance block I/O interfaces like
io_uring and vhost-user-blk. Using libblkio reduces the amount of code
needed for interfacing with storage devices and allows developers to
focus on their applcations.

Add a libblkio engine that uses libblkio to perform I/O. This is useful
to benchmark the library itself, and also adds support for storage
interfaces and devices otherwise not supported by fio, such as
virtio-blk PCI, vhost-user, and vhost-vDPA devices.

See the libblkio documentation [2] or KVM Forum 2022 [3] presentation
for more information on the library itself.

[1] https://gitlab.com/libblkio/libblkio
[2] https://libblkio.gitlab.io/libblkio/index.html
[3] https://static.sched.com/hosted_files/kvmforum2022/8c/libblkio-kvm-forum-2022.pdf

Signed-off-by: Alberto Faria <afaria@redhat.com>
Signed-off-by: Vincent Fu <vincent.fu@samsung.com>