[Thread] add demoapp for Thread network APIs
A screenshot of the demo app:

Bug: 273227725
Change-Id: I8d9bcf00bb54d3f152c436b56df919d967c5b71b
diff --git a/thread/demoapp/res/layout/nav_header.xml b/thread/demoapp/res/layout/nav_header.xml
new file mode 100644
index 0000000..b91fb9c
--- /dev/null
+++ b/thread/demoapp/res/layout/nav_header.xml
@@ -0,0 +1,30 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright (C) 2023 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.
+-->
+
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+ xmlns:app="http://schemas.android.com/apk/res-auto"
+ android:layout_width="match_parent"
+ android:layout_height="wrap_content"
+ android:gravity="bottom"
+ android:orientation="vertical" >
+
+ <ImageView
+ android:id="@+id/nav_header_image"
+ android:layout_width="wrap_content"
+ android:layout_height="wrap_content"
+ android:paddingTop="@dimen/nav_header_vertical_spacing"
+ android:src="@drawable/ic_thread_wordmark" />
+</LinearLayout>