Add microfuchsia apex that runs in AVF on bootup

This requires another apex com.android.microfuchsia.images to be present
that contains a /etc/fuchsia.zbi and /etc/linux-arm64-boot-shim.bin.

Test: Boot up and use console with:
  adb shell -t /apex/com.android.virt/bin/vm console
Bug: b/348687281, b/348434277, b/348433755
Change-Id: I3fe0674d793d37763011f102982f5c3e56b57b5e
diff --git a/microfuchsia/microfuchsiad/src/instance_manager.rs b/microfuchsia/microfuchsiad/src/instance_manager.rs
new file mode 100644
index 0000000..5082e50
--- /dev/null
+++ b/microfuchsia/microfuchsiad/src/instance_manager.rs
@@ -0,0 +1,49 @@
+/*
+ * Copyright (C) 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+//! Manages running instances of the Microfuchsia VM.
+//! At most one instance should be running at a time.
+
+use crate::instance_starter::{InstanceStarter, MicrofuchsiaInstance};
+use android_system_virtualizationservice::aidl::android::system::virtualizationservice;
+use anyhow::{bail, Result};
+use binder::Strong;
+use virtualizationservice::IVirtualizationService::IVirtualizationService;
+
+pub struct InstanceManager {
+    service: Strong<dyn IVirtualizationService>,
+    started: bool,
+}
+
+impl InstanceManager {
+    pub fn new(service: Strong<dyn IVirtualizationService>) -> Self {
+        Self { service, started: false }
+    }
+
+    pub fn start_instance(&mut self) -> Result<MicrofuchsiaInstance> {
+        if self.started {
+            bail!("Cannot start multiple microfuchsia instances");
+        }
+
+        let instance_starter = InstanceStarter::new("Microfuchsia", 0);
+        let instance = instance_starter.start_new_instance(&*self.service);
+
+        if instance.is_ok() {
+            self.started = true;
+        }
+        instance
+    }
+}