Use inode numbers for CE storage.

Certain operations, such as clearing/destroying app data, or just
counting on-disk size, require us to know the CE storage directory
of a particular app.  To facilitate these operations, offer a method
to get the inode of a CE directory, and accept that inode number
for later operations.  Collect and store the inode number in
PackageUserState for future use when that user's CE storage is
still locked.  This design means it's safe to clear/destroy app
data in both CE/DE storage at the same time.

Move most installd-related methods to a uniform calling convention
that accepts a single parent PackageParser.Package, and internally
fans out to handle all "leaf" packages under that parent.

In previous releases, we started installing apps using a new
directory-based layout, where all app code, unpacked native libraries,
and optimized code is bundled together.  So now we only have a single
path to measure for code size.  This fixes several outstanding bugs
that were causing sizes to be miscounted for apps supporting multiple
architectures.

Fix a subtle bug in PackageSettings that would cause "notLaunched"
to be parsed incorrectly.

Bug: 27828915, 27197819
Change-Id: Ia582cf3550553292bde4bb4313367111332913ec