Install constraints API

Design doc: go/installconstraints

Install constraints are the requirements for a session
to proceed installation. The API can be used by app stores
to deliver auto-updates without disrupting the user
experience.

This CL addes PackageInstaller#checkInstallConstraints
which can be used by installers to check whether
constraints are satisfied before installing a package.

Bug: 235306967
Test: atest CtsStagedInstallHostTestCases
Change-Id: I3b66a3bf5b6f9411bdb3ea27d6c4ff11a53a17e0