fuzz: Add fuzzing infrastructure and QCOW fuzzer

Add the basic infrastructure for fuzzing along with a qcow fuzzer ported
from crosvm and adapted to our code.

Signed-off-by: Rob Bradford <robert.bradford@intel.com>

fuzz/Cargo.toml

@@ -0,0 +1,28 @@
+
+[package]
+name = "cloud-hypervisor-fuzz"
+version = "0.0.0"
+authors = ["Automatically generated"]
+publish = false
+edition = "2018"
+
+[package.metadata]
+cargo-fuzz = true
+
+[dependencies]
+libc = "0.2.72"
+libfuzzer-sys = "0.3"
+qcow = { path = "../qcow" }
+
+[dependencies.cloud-hypervisor]
+path = ".."
+
+# Prevent this from interfering with workspaces
+[workspace]
+members = ["."]
+
+[[bin]]
+name = "qcow"
+path = "fuzz_targets/qcow.rs"
+test = false
+doc = false