Add support for user profiles to the Storage Settings.

This adds new preferences for each profile (such as the work
profile) and defines a new view for viewing the storage
breakdown for the individual profile. The functionality closely
mimics the presentation on the main view, but without the system-wide
breakdown and without any additional users/profiles.

Bug: 34715777
Test: Settings Robotests

Change-Id: I19d449b648c6566331fd02e45c2e45f8c74ea7e7