Extract libmicrodroid_metadata (rust_library)

from microdroid_manager. Virtualizationservice will use it to make a
payload disk image.

Bug: 190503456
Test: m
Change-Id: Ifd7d2ef60b7a63dcc373a78dbcbe26f472dc1bc7
diff --git a/microdroid/payload/metadata/Android.bp b/microdroid/payload/metadata/Android.bp
new file mode 100644
index 0000000..4b23394
--- /dev/null
+++ b/microdroid/payload/metadata/Android.bp
@@ -0,0 +1,16 @@
+package {
+    default_applicable_licenses: ["Android-Apache-2.0"],
+}
+
+rust_library {
+    name: "libmicrodroid_metadata",
+    host_supported: true,
+    crate_name: "microdroid_metadata",
+    srcs: ["src/lib.rs"],
+    prefer_rlib: true,
+    edition: "2018",
+    rustlibs: [
+        "libmicrodroid_metadata_proto_rust",
+        "libprotobuf",
+    ],
+}