[Thread] initial Thread network service

This commit sets up the initial Thread network service for the
Android Thread feature which allows an Android device to create
a Thread network and being a Border Router.

See https://www.threadgroup.org/What-is-Thread for background of
Thread.

See b/235016403 for the Android Thread feature request.

Test: lunch aosp_cf_x86_64_tv-userdebug
      m && launch_cvd
      atest CtsThreadNetworkTestCases
Bug: 262683651
Change-Id: Ie1bb23084531f67165ec068ea3ca39592dbc01d1
diff --git a/framework-t/api/system-current.txt b/framework-t/api/system-current.txt
index 64762b4..ea465aa 100644
--- a/framework-t/api/system-current.txt
+++ b/framework-t/api/system-current.txt
@@ -388,3 +388,16 @@
 
 }
 
+package android.net.thread {
+
+  public class ThreadNetworkController {
+    method public int getThreadVersion();
+    field public static final int THREAD_VERSION_1_3 = 4; // 0x4
+  }
+
+  public class ThreadNetworkManager {
+    method @NonNull public java.util.List<android.net.thread.ThreadNetworkController> getAllThreadNetworkControllers();
+  }
+
+}
+