releasetools: Add AbOtaPropertyFiles.

AbOtaPropertyFiles writes 'ota-property-files' into package metadata.
Comparing to StreamingPropertyFiles, AbOtaPropertyFiles additionally
writes a token of 'payload-metadata.bin' for a virtual entry that's head
of the 'payload.bin'. This entry can be used by the system updater to
verify if a payload is applicable to the underlying device.

AbOtaPropertyFiles intends to replace StreamingPropertyFiles, as it
covers all the info of the latter. We keep them both in P, and will
remove the latter in later release.

Bug: 74210298
Test: python -m unittest test_ota_from_target_files
Test: Generate full and incremental A/B OTAs. Check the property-files
      in the METADATA entry.
Change-Id: If5872c8ee0a97a8a95b07d4c69b463aa3fe1b9b9