First commit of dynamic home page feature

- Add SettingsHomepageActivity
- Add feature flag
- Use com.google.android.material_material library

Change-Id: I325be249f739d3b03dc2f0d722319f5771e2313b

res/drawable/ic_list_24dp.xml

@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright (C) 2018 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.
+-->
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="24dp"
+    android:height="24dp"
+    android:viewportWidth="24"
+    android:viewportHeight="24">
+  <path
+      android:fillColor="?android:attr/colorAccent"
+      android:pathData="M4,13L4,13c0.55,0 1,-0.45 1,-1v0c0,-0.55 -0.45,-1 -1,-1h0c-0.55,0 -1,0.45 -1,1v0C3,12.55 3.45,13 4,13zM4,17L4,17c0.55,0 1,-0.45 1,-1v0c0,-0.55 -0.45,-1 -1,-1h0c-0.55,0 -1,0.45 -1,1v0C3,16.55 3.45,17 4,17zM4,9L4,9c0.55,0 1,-0.45 1,-1v0c0,-0.55 -0.45,-1 -1,-1h0C3.45,7 3,7.45 3,8v0C3,8.55 3.45,9 4,9zM7,13h14v-2H7V13zM7,17h14v-2H7V17zM7,7v2h14V7H7z"/>
+</vector>