Implement work-profile infra in BasePreferenceController

- Add settings:forWork in xml
- Set mIsForWork based on xml attribute
- Delete WorkProfilePreferenceController and move its function to
BasePreferenceController

Fixes: 123376083
Test: Add work profile, go to Settings->System->Language&input,
UI should show work profile related items
Change-Id: Id2dcbb0e158c117cdfd363466a275f4e133c345e

src/com/android/settings/location/LocationForWorkPreferenceController.java

@@ -56,9 +56,7 @@ public class LocationForWorkPreferenceController extends LocationBasePreferenceC
 
     @Override
     public int getAvailabilityStatus() {
-        // Looking for a managed profile. If there are no managed profiles then we are removing the
-        // managed profile category.
-        return Utils.getManagedProfile(mUserManager) != null ? AVAILABLE : UNSUPPORTED_ON_DEVICE;
+        return AVAILABLE;
     }
 
     @Override