feat(virtio-mem): implement virtio requests

This commit adds block state management and implements the virtio
requests for the virtio-mem device.

Block state is tracked using a BitVec, each bit representing a single
block.

Plug/Unplug requests are validated before being executed to verify the
range is valid (aligned and within range), and that all blocks in range
are unplugged/plugged, as per the virtio spec.

UplugAll is the only request where usable_region_size can be lowered.

This commit is missing the dynamic KVM slot management which will be
added later.

Signed-off-by: Riccardo Mancini <[email protected]>

Author: Manciukic

Cargo.lock

@@ -23,6 +23,7 @@ aws-lc-rs = { version = "1.14.0", features = ["bindgen"] }
 base64 = "0.22.1"
 bincode = { version = "2.0.1", features = ["serde"] }
 bitflags = "2.9.4"
+bitvec = { version = "1.0.1", features = ["atomic", "serde"] }
 byteorder = "1.5.0"
 crc64 = "2.0.0"
 derive_more = { version = "2.0.1", default-features = false, features = [