DO NOT MERGE: Add a tool for verifying verity signatures in images

This tool takes a sparse ext4 image file, reads verity metadata
from it, and verifies the signature of the verity table.

Bug: 15984840
Bug: 18120110
Change-Id: I384a9ff885a0ffcd8febf100e76f3a1e5c7bbdab
(cherry picked from commit c18aa9d69a69549b50966e322abe59cfa04edfe4)
4 files changed