move xen libraries to xen/

xen/xencall/examples/domain_create.rs

@@ -0,0 +1,11 @@
+use xencall::sys::CreateDomain;
+use xencall::{XenCall, XenCallError};
+
+fn main() -> Result<(), XenCallError> {
+    env_logger::init();
+
+    let call = XenCall::open()?;
+    let domid = call.create_domain(CreateDomain::default())?;
+    println!("created domain {}", domid);
+    Ok(())
+}