Support moving apps to expanded storage.

Start deriving the data path for apps based on the volume UUID where
the app lives.  This path is used for all higher-level APIs, giving
us a clean place to switch app storage.

When parsing a package, keep track of the volume UUID where it lives
and update PackageSetting once installed.  For now continue treating
moves as installs, but we'll eventually clean this up to avoid the
additional dexopt pass.  Wire up move to use the new installd command
to move private data between devices.

Cache LoadedApk only for the current user, since otherwise the data
dir points at the wrong path.

Bug: 19993667
Change-Id: I53336e3b147d5fd3130e6800869af172b628da37