verity_verifier: Support verifying images with FEC.

verity_verifier: Support verifying images with FEC.

The current VerityVerifier.jar cannot verify verity images with FEC
metadata (since N). Replace it with a new verity verifier that uses
libfec to parse and verify verity metadata.

It accepts the same command line arguments as the old verity_verifier
script.

Usage: verity_verifier <image> -mincrypt <verity_key>
  image       the image file (raw or sparse image) to be verified
  verity_key  the verity key in mincrypt format (/verity_key on device)

Bug: 32173582
Test: $ verity_verifier $OUT/system.img -mincrypt $OUT/root/verity_key
      VERIFIED
Change-Id: I8624973715dcd0f6d89d408c1c97bf584b50ce06