Move threadnetwork HAL to VAPEX

com.android.hardware.threadnetwork is a new VAPEX containing
threadnetwork HAL. It also includes ot-rcp.

Bug: 296966113
Test: vts-tf > run vts -m VtsHalTheadNetworkTargetTest
Change-Id: Id2028d755f9b0dcc06ccd817bddf3195efb5595b
diff --git a/threadnetwork/aidl/default/manifest.json b/threadnetwork/aidl/default/manifest.json
new file mode 100644
index 0000000..61e6dc1
--- /dev/null
+++ b/threadnetwork/aidl/default/manifest.json
@@ -0,0 +1,4 @@
+{
+    "name": "com.android.hardware.threadnetwork",
+    "version": 1
+}