Migrate setPackagesSuspended

The underlying package suspension mechanism (PackageManager
.setPackagesSuspendedByAdmin) changes package suspension
state on a per-package basis so we can't simply "push" the
current list of suspended package to PackageManager from
PolicyEnforcerCallback. DPM.setPackagesSuspended() also
returns a list of failed packages which is complex to calculate
under coexistence. As a result, we simply use PolicyEngine
to store the package suspension state, and keep the enforcing
logic in DPMS.

Test: FrameworksServicesTests:SuspendPackagesTest
      android.suspendapps.cts.SuspendPackagesTest
      android.devicepolicy.cts.PackagesTest
      android.devicepolicy.cts.PackageSuspensionTest
      android.devicepolicy.cts.ApplicationExemptionsTest
      MixedDeviceOwnerTest#testSuspendPackage
      MixedManagedProfileOwnerTest#testSuspendPackage
      MixedDeviceOwnerTest#testSuspendPackageWithPackageManager
      MixedManagedProfileOwnerTest#testSuspendPackageWithPackageManager
Bug: 335624297
Change-Id: I9c287d39593d53d69e16ea2ec520df4d12ebcdaa