Add proof-of-rotation information to PackageParser.SigningDetails

APK Signature Scheme v3 enables APK signing key rotation by allowing
an APK to embed a proof-of-rotation structure linking past signing
certificates to the current one.  This information needs to be exposed
to the system before it can be used to make authorization decisions.

Bug: 64686581
Test: Builds and boots.
Change-Id: I49961f92fcec141d73b36197147d5d8fa64c149e