Storage category UX changes in Storage Settings

- Change category types.
- Use Intent.ACTION_VIEW to show content of each category.
- Sort order of each category by storage size.

Bug: 170918505
Test: make RunSettingsRoboTests ROBOTEST_FILTER=StorageItemPreferenceTest
      make RunSettingsRoboTests ROBOTEST_FILTER=StorageItemPreferenceControllerTest
      manual
      Click each category in Storage Settings.
Change-Id: Ib7beb1779a0fcbfd7b8ec52446707b105fcebff5