This is another implementation of the Package class. And we will later
need it when reading the package from FUSE.
Bug: 127071893
Test: unit tests pass, sideload a file package on sailfish
Change-Id: I3de5d5ef60b29c8b73517d6de3498459d7d95975
Creates a new class handle the package in memory and package read from fd.
Define the new interface functions, and make approximate changes to the
verify and install functions.
Bug: 127071893
Test: unit tests pass, sideload a package
Change-Id: I66ab00654df92471184536fd147b237a86e9c5b5