Add Battery Defender feature to Settings

- Reupload CL from ag/13108999 to fix the merge conflict
 - Adding new tips of Battery Defender, will be presented once battery is overheated
 - Launch Help Center article of battery overheat when clicking Battery Defender tip
 Screenshots: https://screenshot.googleplex.com/7jUibTJANgR6UQ6.png
 	      https://screenshot.googleplex.com/tUj2LLi87SfndBN.png

Bug: 172794045
Bug: 173497281
Bug: 173496188
Test: make RunSettingsRoboTests -j40
Change-Id: Ibb106a5d42cdf6232abf9ddf4b3225bdcebccf4a

tests/robotests/src/com/android/settings/fuelgauge/BatteryHeaderPreferenceControllerTest.java

@@ -175,6 +175,15 @@ public class BatteryHeaderPreferenceControllerTest {
         assertThat(mSummary.getText()).isEqualTo(BATTERY_STATUS);
     }
 
+    @Test
+    public void updatePreference_isOverheat_showEmptyText() {
+        mBatteryInfo.isOverheated = true;
+
+        mController.updateHeaderPreference(mBatteryInfo);
+
+        assertThat(mSummary.getText().toString().isEmpty()).isTrue();
+    }
+
     @Test
     public void onStart_shouldStyleActionBar() {
         when(mEntityHeaderController.setRecyclerView(nullable(RecyclerView.class), eq(mLifecycle)))