Schematize Setup Wizard System Properties

Properties accessed across partitions are now schematized and will
become APIs to make explicit interfaces among partitions.

Bug: 117924132
Test: mma -j
Change-Id: Ie6452a01669f5f4de8f74d9e90c6abd4f8e2c33d
(cherry picked from commit 30f595ee1f9b0f1e9d81670ba262f9c1e4af33bd)