Implement Discovery PLATFORM logic in Rust

Add RemoteAuthConnectionCache and RemoteAuthPlatform
with support to sendMessage

Design doc: go/remote-auth-manager-fishfood-design

Test: built successfully.
Bug: : 291333048
Change-Id: I17f73b4fb2e22924a484eeb3baa9b933ae980076
diff --git a/remoteauth/service/jni/Android.bp b/remoteauth/service/jni/Android.bp
index e6e8a43..a95a8fb 100644
--- a/remoteauth/service/jni/Android.bp
+++ b/remoteauth/service/jni/Android.bp
@@ -30,6 +30,12 @@
     host_supported: true,
 }
 
+rust_ffi_shared {
+    name: "libremoteauth_jni_rust",
+    defaults: ["libremoteauth_jni_rust_defaults"],
+    rustlibs: [],
+}
+
 rust_test {
     name: "libremoteauth_jni_rust_tests",
     defaults: ["libremoteauth_jni_rust_defaults"],