Update packages in post-boot background job

Adds a post-boot job which scans all optimizable packages and updates
those whose OAT files are out of date. This is meant to offset the
fact that on OTA we only update the most used packages.

Bug: 27901338
Change-Id: Ia4d4362ecead1ca63d08d62c6814dad4b810f7cc
1 file changed