Align more prefs for icon space.

- Extend preference_category to support summary text
- Removed work_profile_category, used by account list
- align prefs in storage settings
- Use Preference instead of PrefScreen in xmls
- Use proper footer preference in NightDisplaySettings, BatterySaver,
  DataSaver, AutomaticStorageManage
- Remove WallOfTextPreference

Bug: 33775510
Test: visual
Change-Id: I28156b857ff5acac8746c42384dc03d5997ebd9d

src/com/android/settings/datausage/DataSaverSummary.java

@@ -54,6 +54,8 @@ public class DataSaverSummary extends SettingsPreferenceFragment
         super.onCreate(icicle);
 
         addPreferencesFromResource(R.xml.data_saver);
+        mFooterPreferenceMixin.createFooterPreference()
+                .setTitle(com.android.internal.R.string.data_saver_description);
         mUnrestrictedAccess = findPreference(KEY_UNRESTRICTED_ACCESS);
         mApplicationsState = ApplicationsState.getInstance(
                 (Application) getContext().getApplicationContext());