Remove deprecated methods / classes

Now that we've moved the majority of system components to the
PackageInstaller, we can remove the majority of the "installPackage"
methods and the VerificationParams/ContainerEncryptionParams
classes. There are still some lingering references to the two
installPackage() methods left [both internal and external; play
is using these methods via reflection].

Bug: 24542768
Change-Id: Ib65323d842d9f0e7fed60e37e6b5f103c94c859b