[host/client] kvmfr: update to include extra user data about the VM

This change allows the host to provide information to the client about
how the VM is configured, information such as the UUID, CPU
configuration and capture method both for informational display in the
client as well as debugging in the client's logs.

The format of the records allows this to be extended later with new
record types without needing to bump the KVMFR version.

host/include/interface/capture.h

@@ -105,6 +105,7 @@ typedef struct CaptureInterface
   );
 
   bool          (*init         )();
+  bool          (*start        )();
   void          (*stop         )();
   bool          (*deinit       )();
   void          (*free         )();