feat(hostd): varlink interfaced host controller to manage machine configuration and boot mgmt

hostd/src/api.rs

@@ -0,0 +1,17 @@
+use anyhow::Result;
+use dropshot::ApiDescription;
+
+use std::sync::Arc;
+
+use crate::context::ControllerContext;
+use crate::machine;
+use crate::sysupdate;
+
+type ControllerApiDescription = ApiDescription<Arc<ControllerContext>>;
+
+pub fn api() -> Result<ControllerApiDescription> {
+    let mut api = ControllerApiDescription::new();
+    api.register(machine::describe)?;
+    api.register(sysupdate::list_versions)?;
+    Ok(api)
+}