Add a component to load category/tiles by key.

And switch between using SettingDrawerActivity.getDashboardCategories()
and the new CategoryManager in different conditions.

Test: SettingsRoboTests for regression. Will write tests for new feature
soon once we are set on the data structure.
Bug: 31781480

Change-Id: I864e5aea869071df63ca89002fb378c235d0a1fe