Checkpoint of new storage wizards.

Use frameworks/opt/setupwizard/library/ for consistent behavior and
styling on phones and tablets.  Implement every step of wizard flow
and connect them together, even though some steps are currently
non-functional.  All strings to match UX spec, with some adjustment.

Wizards inherit from helper base class.

New interstitials before unmounting or formatting private storage
to confirm user knows consequences.

Bug: 19993667
Change-Id: I2c774e1718d513805ee8aecfc96d066d4730450c