Add CollapsingToolbarLayout for sub settings

Settings app is planning to make toolbar collapsible for next
Android release. This CL is to add a new layout for
CollapsingToolbarLayout in the Settings app and to update the theme
correspondly. This feature will be controlled by feature flag, which
makes Settings app compacitible with the existing layout.

Bug: 174451673
Test: manul test and visual verification
1) Enable the feature and open Settings app
2) Navigate to each sub page and check if toolbar is collapsible

Change-Id: Ibef524bbaa7ae3f0a43db7e40e599f42e009437f