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: I53b16e6d784071a04fe3fe1a9aaac8d5be91077b
(cherry picked from commit d328f613cbe55ba935f23cef081a0f1e1cc40977)