Change new file installs to be cluster-based!

Now that all the other pieces are in place, we're ready to start
installing new file-based packages as a cluster (the new unified
directory-based layout).  This greatly simplifies the renaming
process.

Also add helper methods to ApplicationInfo to give a much clearer
mapping between it and internal field names, since we can't change
the public API.

Add recursive restorecon().

Bug: 14975160
Change-Id: I72a63c5ddbc594c2fec4a91dd59f73ef253fbfd7