Move signing data into SigningDetails container

This change replaces fields from Package that relate to signing
with a single SigningDetails container. It does the same with
InstallArgs and InstallParams. This simplifies much of the code
that would have otherwise relied on synchronizing many fields and
will enable PackageManagerService to make install-time descisions
based on package data instead of forcing it to be part of package
parsing.

Test: android.appsecurity.cts.PkgInstallSignatureVerificationTest passes.
Bug: 68860689
Change-Id: I53bc8c6908b61a54004d1b1d45637be9710ae72f