event_monitor: Add new crate for event reporting

This crate exposes the abililty for the VMM to set a file that events
should be written to. The event!() macro provides an interface to report
those events allowing the specification of an event source, an event
type and optional extra data. This will be written to the provided file
descriptor as JSON data.

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

event_monitor/Cargo.toml

@@ -0,0 +1,11 @@
+[package]
+name = "event_monitor"
+version = "0.1.0"
+authors = ["The Cloud Hypervisor Authors"]
+edition = "2018"
+
+[dependencies]
+libc = "0.2.86"
+serde = {version = ">=1.0.27", features = ["rc"] }
+serde_derive = ">=1.0.27"
+serde_json = ">=1.0.9"