Update SettingsPanel UI

UI changes include:
- RecyclerView to host slices
- Font family to headline font
- Title is now centered
- Added SeeMore & Done buttons
- Horizontal Dividers between slices
- Indented Slices
- Landscape layout is fullscreen

Change-Id: I3549c847fc88edd81f670ddfa2907dd3741441e0
Screenshot: https://screenshot.googleplex.com/RzWktzOZJkc
Test: Robolectric
Test: Manual app
Bug: 118622007

tests/robotests/src/com/android/settings/panel/FakeSettingsPanelActivity.java

@@ -0,0 +1,34 @@
+/*
+ * 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.
+ */
+
+package com.android.settings.panel;
+
+import android.content.ComponentName;
+import android.content.Intent;
+
+public class FakeSettingsPanelActivity extends SettingsPanelActivity {
+    @Override
+    public ComponentName getCallingActivity() {
+        return new ComponentName("fake-package", "fake-class");
+    }
+
+    @Override
+    public Intent getIntent() {
+        final Intent intent = new Intent();
+        intent.putExtra(SettingsPanelActivity.EXTRA_PANEL_TYPE, FakePanelContent.FAKE_KEY);
+        return intent;
+    }
+}