[Tether17] create com.android.tethering.apex package

Add APEX com.android.tethering.apex for tethering module.
It have tethering apk now and would have jar and library
in follow up CL.

Bug:144320626
Test: build
Change-Id: Ie6158639886e90180dd90347e802a5fe062031b2
diff --git a/Tethering/apex/Android.bp b/Tethering/apex/Android.bp
new file mode 100644
index 0000000..bca01eb
--- /dev/null
+++ b/Tethering/apex/Android.bp
@@ -0,0 +1,35 @@
+//
+// Copyright (C) 2019 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.
+//
+
+apex {
+    name: "com.android.tethering.apex",
+    apps: ["Tethering"],
+    manifest: "manifest.json",
+    key: "com.android.tethering.apex.key",
+
+    androidManifest: "AndroidManifest.xml",
+}
+
+apex_key {
+    name: "com.android.tethering.apex.key",
+    public_key: "com.android.tethering.apex.avbpubkey",
+    private_key: "com.android.tethering.apex.pem",
+}
+
+android_app_certificate {
+    name: "com.android.tethering.apex.certificate",
+    certificate: "com.android.tethering.apex",
+}